Alkalinity Help

Tbowser · Nov 4, 2020

In the last week I can't keep my alkalinity up. I can get it to raise but it plummets right back down. Yesterday I woke up and it was 6.8 and throughout the day I was able to get it to 7.5, only to wake up this morning and it is 5.8. My coraline algae is receding so I am pretty sure the test is accurate. I also had my LFS test my water two weeks ago and my ALK reading was the same as theirs.

CA - 446
ALK - 5.8
NO3 - between 5 and 10
P04 - .05
MAG - 1380

Thanks for any help,

-Tim

homer1475 · Nov 4, 2020

What are you using to bring it up, and how much are you raising it in one go?

Tbowser · Nov 4, 2020

I am using Red Sea A/B and am dosing 1.5ml three times a day to raise it 1.5dkh throughout the day.

-Tim

Randy Holmes-Farley · Nov 4, 2020

Do you see substantial abiotic precipitation (like sand clumping)?

That demand is not super high. What is in the tank that might use alk?

What size aquarium?

Tbowser · Nov 4, 2020

It is 14 gallons and it went through a crash about 2 months ago. I only have two small patches of zoas and a small lps coral that survived. Sand seems to be clumping a bit but it breaks up easily if I move it. I did not add my two doses today and the alk is down to 4.9 now.

-Tim

DOJOLOACH · Jan 10, 2021

Randy Holmes-Farley said:
Do you see substantial abiotic precipitation (like sand clumping)?

That demand is not super high. What is in the tank that might use alk?

What size aquarium?

Hey Randy, what is sand clumping a sign of? I found a few golfball sized clumps in a 20lb sand bed. My alk only drops .3 dkh a day or so, is clumping from too low of magnesium?

Randy Holmes-Farley · Jan 11, 2021

It usually happens in new sand, with high pH additives.

If you are concerned about abiotic precipitation, then ways to stop it are:

1. Stop dosing alk for a bit and let it decline.
2. Reduce pH by switching to a low pH alk mix like sodium bicarbonate, or a calcium organic such as Tropic Marin All for Reef.
3. Ensure magnesium is normal to high.
4. Keep organics and phosphate on the high side.

After a few days of not dosing alk, restart slowly, adding additives to a very high flow area so it mixes in fast.