Alkalinity at 15.5, was at 20. How to bring down

[pledosophy]

I came home from vacation to an alkalinity of 20 on my 50g cube. I have done a 20g water change that brought it down to 15.5. How fast can I bring it down to the 8.5?

I have another 5g of water made up, another 5g making. Should I just change 5g every 6 hours to bring it down, or should I just let it come down slowly? I haven't even had an Alk mishap like this so not sure the best course.

The tank is predominantly SPS with some LPS. Sticks all look fine at the moment.

Thank you in advance for your help.

 

[arking_mark]

Nothing good happens fast in a reef aquarium. Whatever you do, I suggest doing it slowly. Corals typically like stability. If it took a week vacation to get to 20...take at least a week to get it back down.

I'd question 20dKH...I recall reading one of @Randy Holmes-Farley articles that showed such a high dKH would cause a precipitation event that would lower Alk/Ca levels.

Water changes with a quality salt are the best way to bring parameters slowly back to your desired levels.

How did this happen?

 

[Acros]

How many times did you test to confirm the 20dkh value? I am also curious to know how it got that high.

 

[pledosophy]

How many times did you test to confirm the 20dkh value? I am also curious to know how it got that high.

4 tests with two different batches of Hanna reagents.

Confirmed again with LFS test.

Did water change and then tested with the two different reagents from Hanna for the 15 reading.

 

[Acros]

I wouldn’t drop more than 1dkh per day. Someone more experienced should be able to give you more direction.

 

[pledosophy]

Nothing good happens fast in a reef aquarium. Whatever you do, I suggest doing it slowly. Corals typically like stability. If it took a week vacation to get to 20...take at least a week to get it back down.

I'd question 20dKH...I recall reading one of @Randy Holmes-Farley articles that showed such a high dKH would cause a precipitation event that would lower Alk/Ca levels.

Water changes with a quality salt are the best way to bring parameters slowly back to your desired levels.

How did this happen?

Thank you.

I was out of town and wrote out instructions for the make up doses if the alk was below 8.5. It appears my reagent went bad while I was gone and the first test the tank sitter did read 2.3 on the Hanna, so he dosed enough to bring it up. The next time they tested it it read 6.1 so they dosed enough to bring it up.

When I got home it looked off. I got a weird alk test, don't remember what but it was strange so I opened a new reagent. Then got the flashing 20's. So I thought wow that new reagent is bad, so I opened a second brand new reagent and had the same results.

 

[Acros]

How are the corals looking?

 

[GARRIGA]

I’ve used Seachem Acid buffer as directed but only attempted 1 to 1.5 dkh drop per day. It works but will temporarily lower PH as it converts alkalinity to CO2 permanently which is then best gassed off.

I’ve only done this with fish but not sure how corals will react to 1.5 drop. Snails and an urchin had no issue. Fish weren’t phased one bit.

Muriatic acid is another approach. Jack Wattley Discus on YouTube has a video on doing that. I prefer the acid buffer. Safer and easy to apply an exact amount.

 

[Doctorgori]

I wanna say it was @Lasse who puts his reagents in the fridge… Who knew?
If you got it down to 15dkh and somehow nothings dead, the perhaps drop it down maybe .3 day, max. and honestly if you can hang with slower, go even slower…
….I’d say 50% of my coral losses seem to be alk swings
good luck

 

[pledosophy]

They actually look great. Some of the LPS is not fully open, but by looking at the tank you can't really see there is a problem.

 

[pledosophy]

How are the corals looking?

Strangely, great for the most part. Some of the LPS is a bit receeded and not as fluffy as normal, but the SPS is open and happy with PE on everything.

 

[pledosophy]

I’ve used Seachem Acid buffer as directed but only attempted 1 to 1.5 dkh drop per day. It works but will temporarily lower PH as it converts alkalinity to CO2 permanently which is then best gassed off.

I’ve only done this with fish but not sure how corals will react to 1.5 drop. Snails and an urchin had no issue. Fish weren’t phased one bit.

Muriatic acid is another approach. Jack Wattley Discus on YouTube has a video on doing that. I prefer the acid buffer. Safer and easy to apply an exact amount.

I don't have any acid buffer on hand. I think if it is safe to go slow I might just do a 5g change everyday until it is normal. The tank itself normally consumes quite a bit of alk a day (I dose 50mL daily) so it will wind itself down soon without me dosing.

 

[pledosophy]

I wanna say it was @Lasse who puts his reagents in the fridge… Who knew?
If you got it down to 15dkh and somehow nothings dead, the perhaps drop it down maybe .3 day, max. and honestly if you can hang with slower, go even slower…
….I’d say 50% of my coral losses seem to be alk swings
good luck

To drop it down by .3 a day I would have to still dose 2 part. My tank will fall 2 dkh a day without dosing. Do you think I should cut my daily dose down from 50mL to say 35mL to have it fall slower?

I was worried 15 dkh in itself could be toxic.

Thanks.

 

[Miami Reef]

To drop it down by .3 a day I would have to still dose 2 part. My tank will fall 2 dkh a day without dosing. Do you think I should cut my daily dose down from 50mL to say 35mL to have it fall slower?

I was worried 15 dkh in itself could be toxic.

Thanks.

Do not dose any more alkalinity until it drops down to a normal range. The corals will drop it down gradually. No need to wean them off that large alk by continuing to does more alk.

 

[Acros]

I agree with the above suggestion, stop dosing and let it fall to desired ranges.

 

[Spare time]

Dropping the alk fast isn't an issue

 

[pledosophy]

Dropping the alk fast isn't an issue

Should I just water change it out/down then? Are you certain?

 

[dvgyfresh]

I accidentally dosed my tank to 20dkh once and I had no losses , the key is water changes and patience. I would not try to lower more than 1-2dkh a day. I simply stopped dosing and did 5g water change every day until it was about 16dkh at which point I just stopped dosing and let it fall naturally. You may need to check salinity , cal , and mg as well to make sure it’s not causing other parameter issues. I dosed calcium while this happend as I didn’t want to drop and maintained it at 450

 

[Lasse]

It works but will temporarily lower PH as it converts alkalinity to CO2 permanently which is then best gassed off.

No it will not work. CO2 only affect pH - not alkalinity. If your corals consume 2 dKH/day - just stop or lower the alkalinity part in your dosing and wait. Keep an eye on Ca levels.

Yes - I store my Hanna reagent in the refrigerator - see here

Important findings according how to store open bottles of the reagent for Hanna Marine alkalinity checkers

There is a way to hinder the Hanna alk to show lesser and lesser dKH (or ppm for that matter) with age of open reagent bottle. I had the same story as many have reported here - my reading decrease from a new open bottle with time. Double check with another method show that there was not a real...

www.reef2reef.com

Sincerely Lasse

 

[Randy Holmes-Farley]

No it will not work. CO2 only affect pH - not alkalinity. If your corals consume 2 dKH/day - just stop or lower the alkalinity part in your dosing and wait. Keep an eye on Ca levels.

He suggested dosing Seachem acid buffer, which will work exactly as he suggested. The CO2 blow off is a side effect, not the "method".