pH question? Should I be concerned

mangups · Mar 10, 2016

I have a 24 gallon (FLUVAL M60 - net volume ~22 gallon)) tank established for a yr +. A few months back my doser malfunctioned and resulted in an ALk overdose. I was able to recover my tank w/o going through a reset. Once the tank was stable again I have started adding corals again and everything is going fine. I have a few SPS (around 10 - including lepto, Acro, monti's etc) and LPS (Acan etc) and some Zoa. Not really a lot of corals.

I just noticed a couple of days back my Alk and Ca an Mg has increased. I noticed it when my pH started showing lower number than previous days. My Ca is 360, Alk is 7.3 and Mg is little low at 1170.

I have been increasing the dosing so that Ca stays as 400, Alk around 7.7 ~8.0( I have found my tank does okay - never tried at 9 etc), Mg usually is 1350 and not sure exactly why it dropped so to 1170. I started adding the BRS 2 part Mg mix so I don't increase more than 25 ppm a day. This will take a few days since I am really going slow on increasing Mg, Ca and Alk. (Need to check fresh mixed saltwater - just to be sure. I have not started a new batch yet)

I have on occasion during the night the pH falling to 7.7 or so. That is the lowest that I have seen is 7.75. During the day it will hover around 8.1 max. The variation is usually within the 0.2 range max during a 24 hr period.

Should I be concerned on pH going below 7.8 on occasions?

Other Parameters
No3 : ~5 ppm
Po4: 0.04 ppm
salinity : 1.026
Light - ATI 6X 24 (Blue +, Coral +, Blue+, coral +) on a 8~9 photoperiod.
Flow : 2 Mp10 at 60% during day and 40 % at night.

My corals look fine -
Here is the Joe Coral pic and a few others...

DannyB · Mar 10, 2016

I would try to increase the O2 and see if it increases your pH. I ran my skimmer air intake outside and this brought my pH up quite a bit. Your corals don't seem to mind right now but that doesn't mean they won't decide they don't like it and take a turn for the worse.

Try the O2 increase and see if this helps.

mangups · Mar 10, 2016

Thanks, not sure how to increase O2. I have a Tunze skimmer and I have the value fully open. I have heard people run a tube to outside the house for the skimmer so that they more fresh air since sometimes the house can have higher CO2.

I have a larger skimmer - Tunze 9004 so I can use that or use an air pump and push air through water using an airstone during the night for couple of hrs.

DannyB · Mar 10, 2016

There may not be enough O2 in the air inside your house, especially during winter. If there is no way of running a tube outside to your air intake you might try just adding an airstone in the sump to oxygenate the water a little more.

Salty1962 · Mar 11, 2016

If your corals are doing well, just keep your levels constant.

Randy Holmes-Farley · Mar 11, 2016

The magnesium drop is almost certainly testing error or due to water changes, unless the time between measurements was many months. Real magnesium consumption is 0-2 ppm per day. typically, and is exactly tied to the calcium depletion rate.

I wouldn't overly worry about low pH, but it is always caused by elevated CO2 in the water when alkalinity is normal, which may be driven by elevated CO2 in your home air.

Solutions include fresher air int he room, bringing in outside air to a skimmer inlet, using higher pH additives for alkalinity (which consume CO2), growing macroalgae, and using a CO2 scrubber on a skimmer inlet.

This has more:

pH And The Reef Aquarium
http://www.reefedition.com/ph-and-the-reef-aquarium/

mangups · Mar 15, 2016

Thank you for the inputs.

I checked the Mg level again and it seems the fresh saltwater is low on Mg. I am using the Red Sea Blue bucket and I tested Mg and it read 1170. I tested twice and I am getting that reading on 1170 (salifert Mg test kit)
The rated values for the Blue bucket is :
@35.5 ppt: pH 8.2-8.4 dKh: 7.8-8.2 Ca: 420-440 Mg: 1250-1310 & K: 380-400

I have over the last few days boosted my level to ideal reef parameters suggest at reefkeeping.com
Here are values over time of 5 days:

Additionally, to combat the low ph. I also adjusted (moved/aligned) the light on the cheato (using a JBL glow magnetic light) and moved the ph probe a left. (Ph probe is in the same chamber as the cheato and the light).
Other than that I added a larger skimmer - this was what I was planning anyways. The new skimmer is rated for 60 gallon (Tunze 9004 from a Tunze 9001 initially).

I also am looking at a C02 scubber and did not go with it since I was travelling and did not want any thing drastically new in the tank.

Everything seemed be okay for 2 days and suddenly last night - I have an email from apex saying on pH increase over 8.30. Over the night ph jumped to 9.0 The pH Jump started at 10:30 pm and kept rising till 7:30 am and then dropped back to ~dKH 8.3 around 8:30 am and to dKH 7.77 around 11am (main lights start at 11 am) . The moment pH hit above 8.3 - I had already turned OFF my Apex Dos (both Ca and Alk) - initial impression is that the DOS got stuck and kept pumping Alk but it does not seem so since Alk dosage for today starts at 12:01 am and ends at 11 am and for yesterday it ended at 11 am. Additionally, the graph shows that for yesterday is pumped 2 ml (the dosing volume I had setup).

Here is the graph for the pH jump:

As of now I am stumped - what happened? what caused this. There are couple of things:
a) pH Probe is conked off - but for now is seems to read what I usually see at this time of the day i.e dKh 7.9
b) is possible that since the pH probe was moved such that is now surround cheato in the chamber and during the night (opposite cycle) there is so much of Co2 consumption to increase the ph to 9. ( light cycle for chaeto is 10 pm to 7 am). If you look at the pH jump is is just around the same cycle time as the cheato light? I think this is most logically explanation.

During this entire time the inhabitants are fine... no ill effects whatsoever. I am guessing the pH oi the display was not the same as being registered same as the refugium area.

I can experiment with not switching the refugium light tonight and see but since generally my system runs in the low pH range I am afraid this time it may have a complete opposite affect.

If there is any inputs I would appreciate you help.

mangups · Mar 16, 2016

I think I figured out the issue...it is to do with the JBL nano glo (refigium/chaeto ) Light. I think the way the probe is positioned caused a lot of reading which are true but give a false impression that something is wrong.

As an experiment i set the refigium light with this apex programming:

And yesterday - the pH reading were as below.

and here is what the apex was doing with the light

If you co-relate the light on with the pH - you can see as the light turn on - the pH increases and then when the pH Increases beyond 8.5 the light turns off an pH decreases. This is what it is doing through the night.

It seems that the probe is just positioned wrong causes you to misinterpret that that the pH is out of wack.

Randy Holmes-Farley · Mar 16, 2016

mangups said:
I checked the Mg level again and it seems the fresh saltwater is low on Mg. I am using the Red Sea Blue bucket and I tested Mg and it read 1170. I tested twice and I am getting that reading on 1170 (salifert Mg test kit)
The rated values for the Blue bucket is :
@35.5 ppt: pH 8.2-8.4 dKh: 7.8-8.2 Ca: 420-440 Mg: 1250-1310 & K: 380-400

.

Well, either the salt is off or the kit is off. I wouldn't assume which it was without more evaluation.

Randy Holmes-Farley · Mar 16, 2016

Where is the pH meter in relation to the lit refugium?

mangups · Mar 16, 2016

Randy Holmes-Farley said:
Well, either the salt is off or the kit is off. I wouldn't assume which it was without more evaluation.

I need to check more on that... I need to test couple of fresh saltwater mixes with 2 test kits and determine if I am making a user error or truly the batch of salt is not mixed properly and we have different Mg content in the bucket.

Randy Holmes-Farley said:
Where is the pH meter in relation to the lit refugium?

The tank is an AIO - see picture of design below.

I have cheato in the middle chamber at the bottom. The light is Nano glo light attached like as shown in 2nd pic (sample pic from the internet) . I have the light almost at the bottom. The probe is also in the same area and now probably sitting in the middle to top of the cheato with the light shining on it. Unfortunately my tank's back is along the wall so cannot get a picture of it. Hopefully this gives you an idea.

Randy Holmes-Farley · Mar 16, 2016

mangups said:
I need to check more on that... I need to test couple of fresh saltwater mixes with 2 test kits and determine if I am making a user error or truly the batch of salt is not mixed properly and we have different Mg content in the bucket.

The tank is an AIO - see picture of design below.

I have cheato in the middle chamber at the bottom. The light is Nano glo light attached like as shown in 2nd pic (sample pic from the internet) . I have the light almost at the bottom. The probe is also in the same area and now probably sitting in the middle to top of the cheato with the light shining on it. Unfortunately my tank's back is along the wall so cannot get a picture of it. Hopefully this gives you an idea.

The pH in a refugium with low flow might get a lot higher than in the main tank, but IMO there is no chance the whole tank actually got to pH 9 unless you greatly overdosed alkalinity.

With respect to the light and possible electrical interference, you can try measuring the pH in a cup of water away from the tank to see if that is an issue (it can be with some pH meters).

mangups · Mar 16, 2016

Randy Holmes-Farley said:
The pH in a refugium with low flow might get a lot higher than in the main tank, but IMO there is no chance the whole tank actually got to pH 9 unless you greatly overdosed alkalinity.

With respect to the light and possible electrical interference, you can try measuring the pH in a cup of water away from the tank to see if that is an issue (it can be with some pH meters).

Yes, very possible. The ph probe is in the back chamber and I don't have a separate for the display so I don't know what the pH values was in the display when the chaeto chamber pH probe was doing it's thing. If there was any overdose I would know since apex would shut off the dosing since it is programmed to shut off dosing when pH reached 8.4 and also the apex fusion is not saying the same. It says it dosed 2 ml of Alk as it was supposed to do.

As for checking the probe... I will check once I get home. I travel for work so will check when I get home Friday.

Well the good thing with all this - I learnt something new. I had no idea pH could swing so much because of light. I am guessing it would not swing so much if it was just light i.e. without cheato. I presume the jump is higher because the cheato is consuming O2 and reducing CO2.

Randy Holmes-Farley · Mar 17, 2016

mangups said:
Well the good thing with all this - I learnt something new. I had no idea pH could swing so much because of light. I am guessing it would not swing so much if it was just light i.e. without cheato. I presume the jump is higher because the cheato is consuming O2 and reducing CO2.

That's correct, it is the consumption of CO2 by the macroalgae that drives up the pH.

Even in natural lagoons, the pH can rise the the upper 8's during the peak times of photosynthsis.

mangups · Mar 20, 2016

I moved the probe to return chamber and we are good with the ph reading. Checked display ph and it is 0.2 higher than the return chamber and varies from 7.9 to 8.1 over a day.

Surfandturf · Mar 20, 2016

mangups said:
Thank you for the inputs.

I checked the Mg level again and it seems the fresh saltwater is low on Mg. I am using the Red Sea Blue bucket and I tested Mg and it read 1170. I tested twice and I am getting that reading on 1170 (salifert Mg test kit)
The rated values for the Blue bucket is :
@35.5 ppt: pH 8.2-8.4 dKh: 7.8-8.2 Ca: 420-440 Mg: 1250-1310 & K: 380-400

I have over the last few days boosted my level to ideal reef parameters suggest at reefkeeping.com
Here are values over time of 5 days:

Additionally, to combat the low ph. I also adjusted (moved/aligned) the light on the cheato (using a JBL glow magnetic light) and moved the ph probe a left. (Ph probe is in the same chamber as the cheato and the light).
Other than that I added a larger skimmer - this was what I was planning anyways. The new skimmer is rated for 60 gallon (Tunze 9004 from a Tunze 9001 initially).

I also am looking at a C02 scubber and did not go with it since I was travelling and did not want any thing drastically new in the tank.

Everything seemed be okay for 2 days and suddenly last night - I have an email from apex saying on pH increase over 8.30. Over the night ph jumped to 9.0 The pH Jump started at 10:30 pm and kept rising till 7:30 am and then dropped back to ~dKH 8.3 around 8:30 am and to dKH 7.77 around 11am (main lights start at 11 am) . The moment pH hit above 8.3 - I had already turned OFF my Apex Dos (both Ca and Alk) - initial impression is that the DOS got stuck and kept pumping Alk but it does not seem so since Alk dosage for today starts at 12:01 am and ends at 11 am and for yesterday it ended at 11 am. Additionally, the graph shows that for yesterday is pumped 2 ml (the dosing volume I had setup).

Here is the graph for the pH jump:

As of now I am stumped - what happened? what caused this. There are couple of things:
a) pH Probe is conked off - but for now is seems to read what I usually see at this time of the day i.e dKh 7.9
b) is possible that since the pH probe was moved such that is now surround cheato in the chamber and during the night (opposite cycle) there is so much of Co2 consumption to increase the ph to 9. ( light cycle for chaeto is 10 pm to 7 am). If you look at the pH jump is is just around the same cycle time as the cheato light? I think this is most logically explanation.

During this entire time the inhabitants are fine... no ill effects whatsoever. I am guessing the pH oi the display was not the same as being registered same as the refugium area.

I can experiment with not switching the refugium light tonight and see but since generally my system runs in the low pH range I am afraid this time it may have a complete opposite affect.

If there is any inputs I would appreciate you help.

What software are you using to monitor this? I'm referring to the graphics you posted. I really like it. Is it free?

Surfandturf · Mar 20, 2016

What is the software you are using to capture all of this data? I really like it.

Randy Holmes-Farley · Mar 20, 2016

mangups said:
I moved the probe to return chamber and we are good with the ph reading. Checked display ph and it is 0.2 higher than the return chamber and varies from 7.9 to 8.1 over a day.

OK, that sounds just fine.