Alk going crazy for no reason

[UCF Alum]

@Randy Holmes-Farley

Background-
-40 gal reef with Carib sea sand bed Bahama pink sand, been underwater approx 1 year
-30 lbs live rock been under water 1 year
-dose 1ppm Nyos nitrate every 3 days (as needed to keep nitrates at 15 so corals/acros don’t starve)
-PO4 runs approx .08ish, give or take
-I use Red Sea blue bucket that I test with Hanna alk checker. Always tests at 8.

I’ve been doing 10 gallon water changes each week to keep my alkalinity at approximately 9.5 to 10. The problem is by the end of the week the alkalinity will creep up to 11.5-12. My acro‘s are starting to burn and I can’t figure out why my alkalinity keeps rising considering I do not dose. I’ve been in this hobby over 30 years and I have no clue as to why this continues to occur weekly. Rocks and/or sand deterioration? I’ve tested my ATO water and it’s not the problem.

-baffled here in Fl….
Help!

 

[Timfish]

Stop dosing nitrate. Coral prefer dissolved organic forms of nitrogen, urea, amino acids and the inorganic form ammonia over nitrate. Just feed your fish more.

FWIW this paper in which the researchers reviewed the data of something like 4 dozen papers found nitrate can have a negative impact on coral calcification.

Here's fig. 3 from the paper

 

[UCF Alum]

Thanks, but how does this affect alkalinity?

 

[Timfish]

Reducing your nitrates will let your corals calcify better using up calcium and alkalinity. Excess nitrogen can disrupt the coral/algae simbiosis reducing the amount of photosynthates the coral has to grow and calcify. I'd keep the nitrates down around 3-5 mg/l leve normally found on reefs and let your PO4 climb a little to what reefs encounter in the wild.

 

[Randy Holmes-Farley Verified Community Expert]

-dose 1ppm Nyos nitrate every 3 days (as needed to keep nitrates at 15 so corals/acros don’t starve)

Dosing nitrate raises alkalinity. Each 50 ppm of nitrate dosed and consumed boosts alk by 2.3 dKH. Not sure if that's the only issue or not.

 

[UCF Alum]

Dosing nitrate raises alkalinity. Each 50 ppm of nitrate dosed and consumed boosts alk by 2.3 dKH. Not sure if that's the only issue or not.

I stopped dosing nitrates. Alk still on the rise. Any other suggestions? I don’t think it’s from dosing nitrates as I only used to dose 2 mls per week.

 

[WrasseyReefer]

Maybe this was discussed and I missed it, but are you dosing alk?

 

[WrasseyReefer]

Maybe this was discussed and I missed it, but are you dosing alk?

Nevermind, I reread it and you don’t. Hmm

 

[WrasseyReefer]

Nevermind, I reread it and you don’t. Hmm

How’s your salinity throughout the week?

 

[WrasseyReefer]

How’s your salinity throughout the week?

Check out this old thread from 2020. They were having similar issue, and it ended up being their sand. If that’s not it, it could also be amino acids if you dose those.

Alkalinity rising without dosing... possible causes?

Over the past month or 2 I've been experiencing the very strange phenomenon of my alk rising without me dosing it. I have a theory as to why that I'd like to run past you all. I reintroduced a decent amount of sand that had been siphoned out of my tank from a while back, that was stored damp...

www.reef2reef.com

 

[UCF Alum]

How’s your salinity throughout the week?

A solid 35ppt. Never moves.

 

[UCF Alum]

Check out this old thread from 2020. They were having similar issue, and it ended up being their sand. If that’s not it, it could also be amino acids if you dose those.

Alkalinity rising without dosing... possible causes?

Over the past month or 2 I've been experiencing the very strange phenomenon of my alk rising without me dosing it. I have a theory as to why that I'd like to run past you all. I reintroduced a decent amount of sand that had been siphoned out of my tank from a while back, that was stored damp...

www.reef2reef.com

I don’t dose anything anymore. Stopped dosing nitrates a few weeks ago. Alk still on the rise. I’m thinking of siphoning part of my sand bed, although it’s only a year old and shouldn’t be the problem. Baffling.

 

[WrasseyReefer]

I don’t dose anything anymore. Stopped dosing nitrates a few weeks ago. Alk still on the rise. I’m thinking of siphoning part of my sand bed, although it’s only a year old and shouldn’t be the problem. Baffling.

You could do an experiment to see if it’s the sand, even if you don’t think it is. Mix up fresh 8.0 alk saltwater, put the water in 2 buckets, one with sand from your tank and the other no sand. Measure the alk every day or so to see if it increases in the sand bucket.

 

[Randy Holmes-Farley Verified Community Expert]

If you are not adding alk somehow, and nitrate and salinity are unchanged, then increasing alk is either test error, or slow calcium carbonate dissolution in the sand and rock pores. Dissolution is normal, and if demand for alk is very low, alk will rise.