Low PH levels in my reef tank.

[TKHAN]

I was wondering if someone could give me advice on my PH level in my 125 gal. reef tank. I can't seem to get my level above 8.01. Currently my tank harbors 100lb. of live rock and 40lb. of crushed coral and sand mix. I have18 soft corals wich seem to be doing fairly well. The tank has been set up with the fore mentiond for about 9 months. I use all Kent products (Turbo calcium- wich I keep around 440) supper buffer- wich I add almost daily, iodine,iron,strot.&moly.,and magn.-wich I try to keep at 1400. I also drip kalkwasser as top off water when ever possible. My alkalinity is on the high side according to my test kit (RedSea). I run a Kent Nautalis skimmer wich seems to do the job vary well. I use a pinpoint PH moniter wich I recalibrate freaquently to insure accuracy. Coraline algea seems to be vary slow growing in my tank. Could this have somthing to do with too much light (3 -175watt metal halides and 2- 160 watt blue atinics)? My amonnia, Nitrite and Nitrate are all virtually undetectable. My Phosphate level is near 0. I do have some silicate cysts on the back of my glass but nothing serious. I use r.o. water, and carbon about 2 weeks out of the month. Any help would be great thanks.........

 

[danmhippo]

Does the pH vary from day and night? How much?

I am speculating if it has anything to do with CO2 content.

One test you could do. Fill a bucket with tank water, drop in an airstone and aerate it for 15 minutes, and take pH reading before and after see if there are any changes to the readings.

This way you can isolate if the problem is with CO2 suppresing the pH level.