Help with Alk

davep · Aug 4, 2023

Hi All, I'm hoping someone might have some insight into an issue I am having.

New tank (Reefer 350) has been online for about 5 months (90 gallon total volume with sump). I have added just a handful of frags and a couple larger corals from an older tank. Everything had been running smooth but my PH was really low (approx. 7.5). I was dosing about 10ml of BRS 2 part daily and maintaining Alk at 8.3-8.5KH.

I decided I wanted to increase the PH which I never payed much attention to in the old tank but never had really good coral growth either.. I added CO2 scrubber to the tank which worked like a charm, I now run PH between 8-8.2. Down side is my Alk immediately crashed and I have been trying to correct it for 2 weeks now with little to no luck. In the last 24 hours my Alk has gone from 7.2 to 6.9 while dosing 90ml of soda ash split evenly across 24 doses. I'm dosing 72ml calcium chloride and Calc is stable at 420. I use a Hana checker to test Alk and its the same reagent I've been using prior to the issue. I swapped out the battery, tried different glass tubes and just ordered more reagent to double check.. I am pretty sure the test result is right but I don't know how it could be...

There is zero precipitation anywhere in the tank and the sand is not clumping in any way.. I dose with 10 minute delay between the two doses and drop into the sump directly into a power head.

90ml daily for what I have in the take seems really off to me.. I keep increasing but Alk just keeps going down no matter how much I add. Going to 120-130ml daily seems crazy for what I have in the tank and I'm worried something else is wrong.. The Goniopora closed is slightly smaller than a baseball and the Blasto probably has 50+ heads but everything else is really small.. I have very little coralline algae at this stage of the tank..

I'm really interested to hear what others think. Am I crazy in thinking there is no way this tank should be consuming this much Alk?

blaxsun · Aug 4, 2023

On my Red Sea 750XXL I dose between 70-90ml of just alkalinity daily to maintain a level between 8.15-8.35dKH, so if you're talking about straight alkalinity - yeah, 90ml seems high for that size of tank.

davep · Aug 4, 2023

blaxsun said:
On my Red Sea 750XXL I dose between 70-90ml of just alkalinity daily to maintain a level between 8.15-8.35dKH, so if you're talking about straight alkalinity - yeah, 90ml seems high for that size of tank.

How is your coral load compared to what I have in the picture?

blaxsun · Aug 4, 2023

davep said:
How is your coral load compared to what I have in the picture?

Fairly substantial (the acro in the center has doubled in size since this was taken).

davep · Aug 4, 2023

blaxsun said:
Fairly substantial (the acro in the center has doubled in size since this was taken).

Really nice looking tank! That confirms I have a problem.. dang.. Now I need to figure out why. I have to go with the test kit is off at this point. I'll head into a local shop to get it tested tomorrow.

Neko · Aug 5, 2023

On my Red Sea 200 (53gal), I dose 15ml of ESV B-ionic 2 part to maintain a level around 7.5dKH at PH 8.2.

To me, PH 7.5 is not easy to believe. Are you living in city, near factory/highway? I suggest to check PH probe with PH solution fluid.

When I buy PH probe, I used without testing. It showed low number. The low number was caused by dried sensor (sensor need to be always wet). It happens.

I maintain my PH.
(1) open window, and
(2) use ESV B-ionic (B-ionic increase PH around 0.2 according to BRS investigation)
My tank is 6 month

blaxsun · Aug 5, 2023

I think everyone's pH is a bit off in North America this year, what with the temperature and smoke from forest firea.

davep · Aug 5, 2023

Neko said:
On my Red Sea 200 (53gal), I dose 15ml of ESV B-ionic 2 part to maintain a level around 7.5dKH at PH 8.2.

To me, PH 7.5 is not easy to believe. Are you living in city, near factory/highway? I suggest to check PH probe with PH solution fluid.

When I buy PH probe, I used without testing. It showed low number. The low number was caused by dried sensor (sensor need to be always wet). It happens.

I maintain my PH.
(1) open window, and
(2) use ESV B-ionic (B-ionic increase PH around 0.2 according to BRS investigation)
My tank is 6 month

It was a brand new probe I added a few months ago and calibrated... That said, I used an AI kit and it reads 8.4 (If I read the color right.. I hate these tests..) when the probe is at 8.1. I'm going to order PH calibration fluid and recal again. Thanks, I would have never checked this.. I did get a co2 monitor in the house when I measured 7.5 and did find that our house would run 1200 ppm if we don't open the windows. We had a good stretch of really hot/humid weather combined with wildfire smoke from Canada that resulted in a sealed home for an extended period. It's new construction and they seal them pretty tight now... probably to tight...