pH too high, alk too low...

spacedcowboy

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Background:
I have a FOWLR tank that I'm getting ready to convert into a reef tank. It's established (for about 6 years now) and I started buying the extras (lights, pumps, trident for monitoring, DOS pumps for dosing) because I know me, and I know the more automated I can get it, the more likely things are to thrive :) Points of note:

  • The tank has always been pretty stable at pH 8.25->8.4, and I wasn't overly concerned about the alkalinity because it only had fish in it.
  • The water is changed at 1 gallon every two hours, and the water source is a filtered supply of real sea-water that is used by all the fish-shops in the local area - I get through about 350G of it per month.
  • There are currently a grand total of 4 small corals in the tank, so I very much doubt there's too much take-up going on that can't be replenished by the water changes.


Problem:
The alk is too low. When I first started the triton up, it was reading about 7.3 for alk, but after running it for a week, going through calibration dropped it down to between 6.95 and 7.1 with a downwards trend. I started dosing alk to bring it up (relatively slowly, it went up from 6.95 to 7.2 yesterday, I expect another rise of 0.3 or so today)

TlqTu90.png

... but I've noticed it creeping up as I have upped the lighting (8.4 was a high for me, usually) and now especially with adding BRS two-part to dose alkalinity higher. I'm not surprised that adding "alkalinity" makes an acid/alkali measurement creep up farther on the alkali scale, what I want to know is how to add the alkalinity and prevent the pH from trending above 8.5 or so. I'm concerned that I've just raised my "floor" level from 8.25-ish to 8.38-ish and I'm about to burst through the 8.5 ceiling today...

Things I'm doing:
  • I've ordered a Hannah Alkalinity meter - so I can check the BRS trident isn't reading me wrong
  • I've just got a new pH probe, and I'm hoping to calibrate/install that tonight (same reason)

Things I'm considering:

I've read Randy's article about lowering pH. My tank is 350G (total water volume) give or take, so if I wanted to lower pH by 0.2, I see I could:
  • Add 1.4 liters of seltzer water, or
  • 230ml of vinegar, or
  • Aerate to add more CO2

The first two I can do, but it would presumably mean an ongoing dose, and ... that's a lot to dose :) The tank is an in-wall one, backing into a (tiny) fish-room with 2' behind the tank, and the room is about 10' across. There's not much space. I was wondering if I was particularly susceptible to low CO2 since it's such a small, relatively-sealed space, and if running air-line tubing to the outside and bubbling air through an air-stone would have a reasonable effect. I have a Whisper 300 air pump sitting there which I think does ~9 liters/minute of air.

Also throwing this out there in case there's something I'm just not seeing - the many eyes of reef2reef might easily spot something I've missed :)
 

vetteguy53081

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Ph is in range and alk as stated is low
You can simply dose alk SLOWLY and increase
Monitor it closely as I like Hanna kits for alk.
Not sure what test kits you are currently using.
The transition should be fairly smooth.
targets:
Ph 7.1-8.3
Temp. 77-79
Salinity 1.025
Nitrate < .4
Phosphate <.04
Ammonia < .03
Mag 1300
Alk. 8-9
Ca 440

if you have API test kits, they will not help you with coral
 

arking_mark

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Background:
I have a FOWLR tank that I'm getting ready to convert into a reef tank. It's established (for about 6 years now) and I started buying the extras (lights, pumps, trident for monitoring, DOS pumps for dosing) because I know me, and I know the more automated I can get it, the more likely things are to thrive :) Points of note:

  • The tank has always been pretty stable at pH 8.25->8.4, and I wasn't overly concerned about the alkalinity because it only had fish in it.
  • The water is changed at 1 gallon every two hours, and the water source is a filtered supply of real sea-water that is used by all the fish-shops in the local area - I get through about 350G of it per month.
  • There are currently a grand total of 4 small corals in the tank, so I very much doubt there's too much take-up going on that can't be replenished by the water changes.


Problem:
The alk is too low. When I first started the triton up, it was reading about 7.3 for alk, but after running it for a week, going through calibration dropped it down to between 6.95 and 7.1 with a downwards trend. I started dosing alk to bring it up (relatively slowly, it went up from 6.95 to 7.2 yesterday, I expect another rise of 0.3 or so today)

TlqTu90.png

... but I've noticed it creeping up as I have upped the lighting (8.4 was a high for me, usually) and now especially with adding BRS two-part to dose alkalinity higher. I'm not surprised that adding "alkalinity" makes an acid/alkali measurement creep up farther on the alkali scale, what I want to know is how to add the alkalinity and prevent the pH from trending above 8.5 or so. I'm concerned that I've just raised my "floor" level from 8.25-ish to 8.38-ish and I'm about to burst through the 8.5 ceiling today...

Things I'm doing:
  • I've ordered a Hannah Alkalinity meter - so I can check the BRS trident isn't reading me wrong
  • I've just got a new pH probe, and I'm hoping to calibrate/install that tonight (same reason)

Things I'm considering:

I've read Randy's article about lowering pH. My tank is 350G (total water volume) give or take, so if I wanted to lower pH by 0.2, I see I could:
  • Add 1.4 liters of seltzer water, or
  • 230ml of vinegar, or
  • Aerate to add more CO2

The first two I can do, but it would presumably mean an ongoing dose, and ... that's a lot to dose :) The tank is an in-wall one, backing into a (tiny) fish-room with 2' behind the tank, and the room is about 10' across. There's not much space. I was wondering if I was particularly susceptible to low CO2 since it's such a small, relatively-sealed space, and if running air-line tubing to the outside and bubbling air through an air-stone would have a reasonable effect. I have a Whisper 300 air pump sitting there which I think does ~9 liters/minute of air.

Also throwing this out there in case there's something I'm just not seeing - the many eyes of reef2reef might easily spot something I've missed :)

Since you are using NSW with AWC (seems like a very large amount), your incoming Alk is probably 7ish. Also, higher pH typically means higher Alk consumption, including abiotic precipitation. So I think your #s look fine to me. I wouldn't tweak anything at this point.
 
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spacedcowboy

spacedcowboy

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Ph is in range and alk as stated is low
You can simply dose alk SLOWLY and increase
Monitor it closely as I like Hanna kits for alk.
pH is in range right now (it's 8.43 as I type) - but I'm concerned about later today. If the swing goes as it has for the last few years, it's going to break 8.5 this afternoon which is where I start wanting to correct it. Just trying to get ahead of the game rather than react :)

Not sure what test kits you are currently using.
The transition should be fairly smooth.
targets:
Ph 7.1-8.3
Temp. 77-79
Salinity 1.025
Nitrate < .4
Phosphate <.04
Ammonia < .03
Mag 1300
Alk. 8-9
Ca 440

if you have API test kits, they will not help you with coral

Temp is 78 +/- 0.2
Salinity is 34.1 (or ~1.026)
Ammonia isn't detectable
Mag is 1318
Ca is 426

... and the last time I tested, phosphates were 0.08. I've asked the wife to get some vodka on the next shopping trip to start slowly dosing that as well. You have reminded me that I haven't tested for nitrates recently though, my tests ran out and I've just ordered more :)

Since you are using NSW with AWC (seems like a very large amount), your incoming Alk is probably 7ish. Also, higher pH typically means higher Alk consumption, including abiotic precipitation. So I think your #s look fine to me. I wouldn't tweak anything at this point.

So I'm assuming that the alk is typical seawater (7 or thereabouts), although I haven't actually tested the stuff in the storage tanks, just what's in the display.

What I was trying to do was get it up to 8-ish - I'm assuming I have to match the incoming seawater replenishment + whatever consumption is happening (which oughtn't be much right now, as I said).

You're right that I change a lot of water, but that's for a few reasons:
  • The water clarity seems to be that tiny fraction better that makes a huge visual difference when it's changed frequently, my dad recently told me it looks as though the fish are flying because you can't see the water
  • I have to use a certain amount every month to keep the supplier interested - not quite as much as I actually do use though - I'd need to get through ~250G/month to make it worth his time to drive to my house and fill up the storage tanks.
  • When I started doing this, the tank was young, and frequent water changes were very useful. I guess I just never stopped. I could dial it down a bit now, but ...

Thanks for the input, folks - I do really appreciate it. I guess I'll keep a close eye on the pH today and see what it oscillates between.

Any comments on the low CO2/airstone idea ?
 

arking_mark

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pH is in range right now (it's 8.43 as I type) - but I'm concerned about later today. If the swing goes as it has for the last few years, it's going to break 8.5 this afternoon which is where I start wanting to correct it. Just trying to get ahead of the game rather than react :)



Temp is 78 +/- 0.2
Salinity is 34.1 (or ~1.026)
Ammonia isn't detectable
Mag is 1318
Ca is 426

... and the last time I tested, phosphates were 0.08. I've asked the wife to get some vodka on the next shopping trip to start slowly dosing that as well. You have reminded me that I haven't tested for nitrates recently though, my tests ran out and I've just ordered more :)



So I'm assuming that the alk is typical seawater (7 or thereabouts), although I haven't actually tested the stuff in the storage tanks, just what's in the display.

What I was trying to do was get it up to 8-ish - I'm assuming I have to match the incoming seawater replenishment + whatever consumption is happening (which oughtn't be much right now, as I said).

You're right that I change a lot of water, but that's for a few reasons:
  • The water clarity seems to be that tiny fraction better that makes a huge visual difference when it's changed frequently, my dad recently told me it looks as though the fish are flying because you can't see the water
  • I have to use a certain amount every month to keep the supplier interested - not quite as much as I actually do use though - I'd need to get through ~250G/month to make it worth his time to drive to my house and fill up the storage tanks.
  • When I started doing this, the tank was young, and frequent water changes were very useful. I guess I just never stopped. I could dial it down a bit now, but ...

Thanks for the input, folks - I do really appreciate it. I guess I'll keep a close eye on the pH today and see what it oscillates between.

Any comments on the low CO2/airstone idea ?

Are you using a skimmer?

 
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spacedcowboy

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Are you using a skimmer?


Yep. A Bubble King SuperMarin 250, and it's just had the pinwheel changed on the RD3 Speedy pump.

There are plenty of bubbles in the skimmer section of the sump, and the skimmer is working well, but I was thinking that the small enclosed space of the fish-room (really just the back of the tank + 2 feet) might mean the air being mixed into the water by the skimmer was CO2-deficient. That was why I was thinking an air-line to outside...

The "fish room" only has an external door (no window) and a bathroom extraction fan that's pretty much on constantly to cope with humidity. There is a small hole in the ceiling of the room to the attic crawlspace, to allow an ethernet cable through, but that's basically the only place air could get in apart from the sealing around the doorway (which is pretty well sealed).
 

arking_mark

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Yep. A Bubble King SuperMarin 250, and it's just had the pinwheel changed on the RD3 Speedy pump.

There are plenty of bubbles in the skimmer section of the sump, and the skimmer is working well, but I was thinking that the small enclosed space of the fish-room (really just the back of the tank + 2 feet) might mean the air being mixed into the water by the skimmer was CO2-deficient. That was why I was thinking an air-line to outside...

The "fish room" only has an external door (no window) and a bathroom extraction fan that's pretty much on constantly to cope with humidity. There is a small hole in the ceiling of the room to the attic crawlspace, to allow an ethernet cable through, but that's basically the only place air could get in apart from the sealing around the doorway (which is pretty well sealed).
An air line to the outside would most likely decrease CO2 and increase your pH. I don't know how your inside air would have less CO2.
 

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Yep. A Bubble King SuperMarin 250, and it's just had the pinwheel changed on the RD3 Speedy pump.

There are plenty of bubbles in the skimmer section of the sump, and the skimmer is working well, but I was thinking that the small enclosed space of the fish-room (really just the back of the tank + 2 feet) might mean the air being mixed into the water by the skimmer was CO2-deficient. That was why I was thinking an air-line to outside...

The "fish room" only has an external door (no window) and a bathroom extraction fan that's pretty much on constantly to cope with humidity. There is a small hole in the ceiling of the room to the attic crawlspace, to allow an ethernet cable through, but that's basically the only place air could get in apart from the sealing around the doorway (which is pretty well sealed).

It seems highly unlikely the mixing fresh air from outside will increase the co2 in the water. I guess possible, but that would seem very odd to me. Can always hook an airline up to your car exhaust for the extra co2 :)
 

Randy Holmes-Farley

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The pH is unlikely to get "too high".

if it does get up to pH 8.6 or higher (and is real, most often that is test error), more aeration alone will bring it down, and switching to lower pH alkalinity supplements (baking soda) will help.
 

Randy Holmes-Farley

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It seems highly unlikely the mixing fresh air from outside will increase the co2 in the water. I guess possible, but that would seem very odd to me.

Agree. Indoor air is not ever depleted in CO2 if a person is in the room.
 
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spacedcowboy

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It seems highly unlikely the mixing fresh air from outside will increase the co2 in the water. I guess possible, but that would seem very odd to me. Can always hook an airline up to your car exhaust for the extra co2 :)

I'll ... bear that in mind :)

An air line to the outside would most likely decrease CO2 and increase your pH. I don't know how your inside air would have less CO2.

Ok, so maybe I was getting the wrong end of the stick when reading about it. Looking again, it seems houses are likely to have more CO2 in them than outside :(

Regarding people in the room - 99% of the time there's no-one in the "room" - what we did was make a "fish room" by sealing off one end of the living room and putting in an outside door...

YESln5j.jpg
... and then build a wall across (more or less) the front of the tank...

gMotH3p.jpg

The only time there's someone in the "fish-room" (better: fish-closet) is when I'm cleaning / installing something.

I do intend to double-check the tests (both pH and alkalinity), waiting on the Hanna checker for alk, and I'll calibrate/install a new pH probe this evening. It's been about a year since the last one was installed, so I was planning on putting in a new one anyway.

So if "more aeration" brings it down, that's a yes for the air-line, but no point in going outside, right ? :)
 

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I'll ... bear that in mind :)



Ok, so maybe I was getting the wrong end of the stick when reading about it. Looking again, it seems houses are likely to have more CO2 in them than outside :(

Regarding people in the room - 99% of the time there's no-one in the "room" - what we did was make a "fish room" by sealing off one end of the living room and putting in an outside door...

YESln5j.jpg
... and then build a wall across (more or less) the front of the tank...

gMotH3p.jpg

The only time there's someone in the "fish-room" (better: fish-closet) is when I'm cleaning / installing something.

I do intend to double-check the tests (both pH and alkalinity), waiting on the Hanna checker for alk, and I'll calibrate/install a new pH probe this evening. It's been about a year since the last one was installed, so I was planning on putting in a new one anyway.

So if "more aeration" brings it down, that's a yes for the air-line, but no point in going outside, right ? :)

Right.

But if you are already running a skimmer full time...I'm not so sure your pH reading is accurate.
 

vetteguy53081

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Take a water sample to a trusted LFS and have them test the water for you and see what results they come up with as a second opinion
 
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If it's humans breathing that's the main driver of high CO2, perhaps I ought to banish the kid in there for a few hours a day. Putting a Nintendo Switch in there ought to be sufficient :) Might have to chain it to the tank to keep him there though...

But if you are already running a skimmer full time...I'm not so sure your pH reading is accurate.

Looking at your thread, it seems your skimmer took it up by ~0.2. I can get the Apex to monitor pH and modulate with the skimmer, but I'm wary of taking away the main filtering I have on the water. Certainly something I could try, though. The current pH probe is pretty close to the skimmer (in the sump, next compartment after the bubble trap). It might be instructive to measure in the tank itself...

The LFS test idea is a good one as well - next time I go, I'll do that :)

pH up to 8.45 and I've stopped the alk dosing for the time being. I can resume that tomorrow if all is ok.

Baking soda is a good idea as well, rather than soda ash. Thanks @Randy Holmes-Farley
 

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What time of day do you do your alk dosing? If you're using the Apex doser, you can overlay the alk chart and ph chart to see impact..
 
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What time of day do you do your alk dosing? If you're using the Apex doser, you can overlay the alk chart and ph chart to see impact..
Good point. There does appear to be a correlation...

RdiNhJo.png

I switched dosing off at 6AM today (when I get up) - it'll be interesting to see where the graph goes today.

Please ignore the big blue spikes - I'm fairly certain that was when I was re-priming the pumps (I had a loose connection and was getting air bubbles until I figured it out and tightened them).
 

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If it's humans breathing that's the main driver of high CO2, perhaps I ought to banish the kid in there for a few hours a day. Putting a Nintendo Switch in there ought to be sufficient :) Might have to chain it to the tank to keep him there though...



Looking at your thread, it seems your skimmer took it up by ~0.2. I can get the Apex to monitor pH and modulate with the skimmer, but I'm wary of taking away the main filtering I have on the water. Certainly something I could try, though. The current pH probe is pretty close to the skimmer (in the sump, next compartment after the bubble trap). It might be instructive to measure in the tank itself...

The LFS test idea is a good one as well - next time I go, I'll do that :)

pH up to 8.45 and I've stopped the alk dosing for the time being. I can resume that tomorrow if all is ok.

Baking soda is a good idea as well, rather than soda ash. Thanks @Randy Holmes-Farley

My natural tank pH in my house is 7.9. I'm using the skimmer with the CO2 scrubber to boost my pH. However, during peak lighting, when pH gets a little to high, I remove the scrubber and use the skimmer to push down the pH. Let me have a super steady pH.

This only works because of my higher CO2 indoor air.

If you're already running you skimmer 24/7 with indoor air, you're not going to lower your your current pH.

However, hitting 8.5 without a CO2 scrubber seems highly unlikely. Especially with a 24/7 skimmer. So I think your pH reading is off.

With such a large AWC, you can easily push up alk with simple baking soda that you can add to the AWC. Just remember not to unbalance your tank.
 

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Good point. There does appear to be a correlation...

RdiNhJo.png

I switched dosing off at 6AM today (when I get up) - it'll be interesting to see where the graph goes today.

Please ignore the big blue spikes - I'm fairly certain that was when I was re-priming the pumps (I had a loose connection and was getting air bubbles until I figured it out and tightened them).
Yes, I dose alk during the valleys, and ca during the peaks.. it helps level it out.. and I bet you're dosing near your ph probe?
 
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Yes, I dose alk during the valleys, and ca during the peaks.. it helps level it out.. and I bet you're dosing near your ph probe?
That's a good idea :)

The probes are separate though, the DOS dumps into the raceway for the overflow, then it travels down to the sump, through the skimmer partition, through the bubble trap and the probes are just above the return inlet (a Reeflo Dart) so both source and sink are in a reasonably high throughput area.
 
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