pH swings

[ShaunV]

Hello all,

Just wondering if anyone has any experience with their pH getting really high (9.0) during the day and dropping back down to 8.3 at night. I am having this issue and I don't know how to stop it. I had the red algae "Macro Feast" by reef nutrition in my tank. I removed it thinking the plant was taking all of the CO2 out of the tank and causing the swing. The plant has been out for 2 days now and I am still getting the swings. My Alkalinity is at the lower end of the "normal" range. I am wondering if I should wait it out, add pH down when the pH is high or add Alkalin8.3 (buffer) when the pH is normal to help lock the pH in place. Any suggestions would be great. I do have some livestock and I am trying to avoid killing everything from the pH swings.

Thanks in advance for advice.

16.75 gallon tank
30 lbs of LS
22 lbs of LR
2 power heads
No filters.
Temp 79.8
Ammonia 0
Nitrites 0
Nitrates 0
salinity 1.024
Alkalinity 1.7 meq/l
pH swinging between 8.3 and 9.0

 

[ShaunV]

I feel it could also be the fact that the Alkalinity is too low which could cause pH swings. I am building alkalinity up by 1.1meq/l to get a reading of 2.8 meq/l the bottle of alkalin8.3 lists the acceptable alkalinity range is 7-12 dKH or 2.5-4.3 meq/l. I will probably bring it up a little higher because I know alkalinity will go down with creatures in the tank.