Alk spike and slowdown in coral growhv

[Studjunior]

Hi everyone,

Everything seemed to be going great in my tank but I recently noticed that some of my SPS corals which were growing like crazy all of a sudden stopped or slowed growing. A couple of weeks ago I did a water change and checked my parameters and everything looked ok. Alk 9.5. Cal 400 phos .05 mag 1250. I increased my calc dosage of my 2 part (BRS) and dosed mag to raise it a bit.

I was preparing to do a water change tonight and thought I would check my levels pre water change (I always test the day after a water change).

These are my levels pre water change:

Alk 12 (Hanna)
Cal 410 (Hanna)
Mag 1270 (salifert)
phos .04 (Hanna)

I don't know what would have caused such a high spike in my Alk considering I haven't changed the amount of 2 part being dosed. The only thing I can think of is that if due to the sudden halt in coral growth from my SPS corals the consumption rate dropped. I don't know what has caused some of my corals to stop growing though. The only recent change made to my system was raising how high up my light fixture was hanging (I raised it a couple of inches) and i started using KZ Amino Acid and Phol Extra but these changes were made after I noticed the stop in growth.

Any insight would be greatly appreciated.

[m and m]

Did you take out any big pieces of SPS or lose any pieces? Are you sure on those numbers if it was with a hanna checker I would clean the vile and just double check it.

[ritter6788]

I've been there. I almost crashed my whole tank after switching MH bulbs and the growth was less. Raising your lights up could be enough to slow growth and alk consumption and cause and alk spike. Any time you make even small changes to your tank alk, should be monitored several times a week if not daily.

[Studjunior]

Did you take out any big pieces of SPS or lose any pieces? Are you sure on those numbers if it was with a hanna checker I would clean the vile and just double check it.

I have not lost or taken out any SPS. I made sure the Giles were clean. I plan on doing another water change tonight and will test the parameters again to be sure what hey are at. My T5s are closing in on 10 months old. I intend on changing them out at the beginning of August. These are some SPS that are still growing but other have just stopped growing.... Everything else looks healthy.