Corals stopped growing

[hkgar]

Well at least significantly slowed down. I month ago I was using close to 2 dKH per day and it has slowed to less than 1 dKH.

Tank is lit with 2 250 W Radiums and 4 80 W t5's T5's on from 9:00 AM to 8:00PM and MH from 11:00 til 07:00PM

Last test last weekend
PO4 .03
Nitrates 5
Today
dKH 8.0
Ca 445
Mag 1365
Ph 7.7
Temp 79-82

Why would growth slow so much? I have been running low ph (7.5 -7.7) for awhile. It is up to 7.8 today

Flow from two gyre 250 (70%) + 650 GPH return.

 

[outssider]

has the ph changed ? ph seems a bit low, are you sure that's an accurate ph measurement. do you have a lot of people in a closed up house, this will increase the co2 in the room and lower ph.

 

[reefmutt]

I wouldn't over think it..
If corals are looking good and healthy, let it ride.
Ph does seem a bit low.. if it's only 7.8 during the day, it could be getting pretty low at night..
Windows closed up for air conditioning?
Outsider may have a point about co2 buildup..
But in general your numbers look pretty good..

 

[Usernam Invalid]

Photo period for the halides is a bit long but if tank always been that way wouldn't be a concern.

How old is your bulbs? Any other changes to the system?