Alkalinity help

[austinl]

Hey guys,

Just have a puzzling question, my tank has undergone a slight reboot where I have stopped all dosing as i lost my sps so I decided to rescape and ensure my flow in the tank was up to par with no dead spots and better paths so to speak.

I monitor / test my alk every two days sometimes daily and it’s always 8.4-8.8 when I measure the tank.

However when I test my water change water the alk is always 7-7.4 (all other parameters are fine Ca/Mg as they closely match tank)

I’m not currently correcting my water change to match my tank values and week after week my alk seems to stay consistent with no dosing.

I’m using aquaforest reef salt and it’s mixed in a covered 30 gallon brute.

I’m not concerned so much with the overall number (I’m looking to have it around 8-9) but in concerned that I might run into issues when I add SPS and begin dosing again as i would expect i would have to match my water change water at that point.

My other tank values are as follows
100 gallon total volume

Water change is 20% weekly

Ph ranges 8.05(night) 8.20 (daytime)
Salinity 1.024-1.025
Ca 435
Mg 1400
NO3 5-10ppm
PO4 0.04/0.08

Rock is/was dry rock and substrate is Argonite sand, lighting is T5



Thanks for the help guys

 

[Diesel]

First of don't chase the magic #, 7.7 isn't that bad if I tell you that I had a tank full of SPS colonies and with a CaRx I kept my ALK around 7.5 as I didn't want the coralline algae to over power the tank and I have to dose much more.
If you do a 20% WC on a 100 gallon tank with a ALK # of 9 you can drop of full #.
If you do a 10% WC twice a week (which I recommend for SPS) your ALK doesn't drop crazy and with manual dosing you can keep it up.
I'm pretty sure you have a ATO and @Randy Holmes-Farley can tell you all about how to tackle that and keep track and balance on the main three.

 

[austinl]

Thanks for the reply Diesel.

I’m definitely not worried about chasing a number just more interested to find out why my alk is higher in the tank without dosing when my freshly made saltwater has a lower alk reading than the tank.

I do have an ATO and doser but the doser is offline as water changes are keeping it stable for now.

 

[Diesel]

You use the same test kit to test your newly mixed water and water in the DT?
What kind of sand and rock in the tank?
You using any dead corals as decoration?

 

[austinl]

You use the same test kit to test your newly mixed water and water in the DT?
What kind of sand and rock in the tank?
You using any dead corals as decoration?

Yeah I use the exact same test kit and have tried two different kits (Red Sea and Aquaforest)

No dead coral decorations and tank was started with dry rock and argonite for the sand.

 

[Diesel]

Weird!!
But that's the reason of this thread of course
Let's do this the Sherlock method .............. So your new water 7/7.4 and after a water change your tank 8.4/8.8
You did dose but you stopped cause your SPS went RTN .....................
Only explanation I can give is that you dosed too much and balance was all over the place and the ALK got absorbed into the sand and rock and now it is releasing it.
That's why you don't see any changes in your ALK.
My suggestion is now that you don't have any SPS to keep up what your doing and stable the balance out in your tank.
If you don't dose with a ALK level of a 8.5 average and new slat mix is average 7.5 there comes a point of time your tank will balance out around that 7.5.
If you reach that point you can pick up the dosing again to get your tank back to the 8.5 mark and get ready for SPS.
But let me ask you this, in this hobby we all keep track of our test results everyday as we walking a fine line to master the keep or get close to a natural balance in order to have happy corals, when your SPS took a turn for the worse what were your parameters?
Only then you can go back and see what went wrong, if parameters were fine than I suspect maybe a pest that went after your hard earned SPS corals.
Without these results you could make the same mistake and do it again.
I could tell you my test results from last year and the year before and 2010 and 2005 even 1990 and I guess 1985 as well if I can find my notebook.

 

[CNDReef]

How high is your no3?
If high your tank bacteria could be making alk as a byproduct of consuming the no3

 

[austinl]

Weird!!
But that's the reason of this thread of course
Let's do this the Sherlock method .............. So your new water 7/7.4 and after a water change your tank 8.4/8.8
You did dose but you stopped cause your SPS went RTN .....................
Only explanation I can give is that you dosed too much and balance was all over the place and the ALK got absorbed into the sand and rock and now it is releasing it.
That's why you don't see any changes in your ALK.
My suggestion is now that you don't have any SPS to keep up what your doing and stable the balance out in your tank.
If you don't dose with a ALK level of a 8.5 average and new slat mix is average 7.5 there comes a point of time your tank will balance out around that 7.5.
If you reach that point you can pick up the dosing again to get your tank back to the 8.5 mark and get ready for SPS.
But let me ask you this, in this hobby we all keep track of our test results everyday as we walking a fine line to master the keep or get close to a natural balance in order to have happy corals, when your SPS took a turn for the worse what were your parameters?
Only then you can go back and see what went wrong, if parameters were fine than I suspect maybe a pest that went after your hard earned SPS corals.
Without these results you could make the same mistake and do it again.
I could tell you my test results from last year and the year before and 2010 and 2005 even 1990 and I guess 1985 as well if I can find my notebook.

Indeed it is weird, I am also thinking something along the lines as something is buffering the water but can’t figure out what.

Let’s add a timeline to this as well, the SPS was lost in August, so since then as I stated earlier I reworked my aquascape to get better flow dynamics and prevent sand storms so I could run my pumps at a higher level (running MPs 40s on opposite sides to run alternating gyre).


Prior to losing my SPS alk was kept in a range of 7.8 and was very stable until at one point alk had hit a high of 9 after a power outage but then it settled back down slowly as i let it fall back slowly.


So since the let’s call it a rebuild in August I have kept the weekly water changes up which has brought us here with the same result higher Alk in the tank with the water change being a lower alk level.

Now everything else in the tank has done very well mushrooms have gone crazy, torch has tripled in size and my porites is doing good.

I have recently added 4 nice little frags of SPS back which is why I’m trying to get this mystery solved.

I can say that I think the SPS was lost from other reasons

One of the new frags was looking poor so I stayed up one night and found this guy who must have been hiding for a very long time and has now been removed to the sump and that particular piece has healed nicely.

The only other pests I am working to eradicate are vermitid snails I think.

 

[austinl]

How high is your no3?
If high your tank bacteria could be making alk as a byproduct of consuming the no3

NO3 is 5-10ppm

 

[austinl]

Just testing this morning with both kits, and all measured 8.4-8.7 after yesterday’s water change with NSW of 7.2

 

[Diesel]

Ok good job.
That crab is a gorilla crab and will munch on acros whole day every day.
The few pieces will be your indication if things are good or bad.
I suggest just keep up the waterchange schedule only.
When your AF salt is done try to skip, I'm using for 7 years the tropic marine and it never let me down.
Noticed that other ppl have problems with AF salt as well.

 

[austinl]

Ok good job.
That crab is a gorilla crab and will munch on acros whole day every day.
The few pieces will be your indication if things are good or bad.
I suggest just keep up the waterchange schedule only.
When your AF salt is done try to skip, I'm using for 7 years the tropic marine and it never let me down.
Noticed that other ppl have problems with AF salt as well.

I have heard some users have issue with high MG or CA but this is opposite of that.

I can’t see changing salt fixing the issue because most salts are higher ALK for the most part which might make the problem worse so I’m hoping we can figure this out first before change such as that.

I am glad I found that crab not sure what he was eating all this time with no SPS in there.

 

[dgrigor02]

For clarrification, have you taken a alk reading of show tank just minutes before your water change ? You say new saltwater is around 7.2 and after is 8.4 but what is the tank just prior to water change ? If its not higher than 8.4 then there is got to be a testing error somewhere.

 

[austinl]

For clarrification, have you taken a alk reading of show tank just minutes before your water change ? You say new saltwater is around 7.2 and after is 8.4 but what is the tank just prior to water change ? If its not higher than 8.4 then there is got to be a testing error somewhere.

I’m pretty sure its not a testing error, using two different kits and daily testing.

I let my NSW mix for 24 hours before it’s tested and my tank reading are every second day normally but have done daily recently.

That said my NSW mixes for 24 hours and is added/changed every Tuesday, i then allow 24 for the tank to settle before retesting and then retest until next water change.

Hence why I am posting here it’s a riddle I can’t solve.

 

[dgrigor02]

and the alk reading just prior to water change was ?

 

[Randy Holmes-Farley]

How many weeks has this been going on? The alk drop from one 20% change will be hardly noticeable. Only like 0.2 dKH.

 

[austinl]

How many weeks has this been going on? The alk drop from one 20% change will be hardly noticeable. Only like 0.2 dKH.

Hey Randy this has been ongoing since the end of August which is why i finally decided to post this up.

 

[austinl]

and the alk reading just prior to water change was ?

8.4 would have been the reading prior, as I said I perform my water change and retest after 24 hours to allow for everything to equalize.

 

[Randy Holmes-Farley]

I think the effects you are looking for are quite small. Like 1 dKH or less over a month or two. There can be minor reasons for alk to rise or fall a small amount over such periods, and I wouldn’t agonize over it.

 

[austinl]

I think the effects you are looking for are quite small. Like 1 dKH or less over a month or two. There can be minor reasons for alk to rise or fall a small amount over such periods, and I wouldn’t agonize over it.

I know we are looking at a small number 1.6 or so dKH, but over the course of two months should this not have corrected itself to my NSW values?

I’m really only concerned as I add SPS back want to be able to calculate dosing appropriately.