Ok, Here is the scoop, 29g biocube, 10 gal fuge, 5.5g frag tank all tied in one system. I have had a problem lately where my PH is around 7.8 (API Test) and my Alk is 9.2ish, my Calcium is 420-430 (salifert tests). I add approx 15-18mL of Natureef Calcium Plus and Alkalinity Plus every morning several hours before the lights come on. I have tried adding more of the supplements and even tried a little bit of PH Buffer 8.2 with no change in my PH level. Some corals are getting bleached from it and some SPS wont give me any PE... any ideas?????

7.8 is fine.. your problem is trying to chase the perfect number.. stability is better than the number. 9.2 isn't really low.. 9-11 is ideal. Either you don't have enough surface agitation or you have excess CO2 in the house.. open a window for a day and see if you get a change in the pH.. or aerate a cup of tank water outside. If the pH raises by .1 or higher.. you have an issue with indoor CO2.

Both are in the normal ranges, so you should do nothing. I'm guessing you measured pH when the lights in the tank had been off or on for a short time (i.e. normal pH swings). pH is one thing you really don't want to be messing with for its own sake. Alkalinity (mainly bicarbonate for SW tanks) is the major influence in tank pH and is more important.

Why do you think you need to be dosing? What kind of corals do you have?

Do you have links to what you're dosing? I'm not familiar with those products.

Read this:
http://reefkeeping.com/issues/2004-05/rhf/index.php

My PH is generally well maintained at 8.2-8.3, and my alk is generally closer to 11, these have dropped more than what I like and what the tank likes, I have had it drop down before for a lil more than a week and then it popped back up, then and now i noticed bleaching in my montis and lack of pe in my acros. Natureef Alkalinity and Hardness Plus For the moment I have increased the surface irritation and will hope that this helps. Any other suggestions?

Water change?? That's all i can think of to re-stablize the numbers... I wouldn't fret at 7.8 and 9dKH though, both like said are within range. I'd understand if you were chasing numbers like 7.5 and 4dKH like I had around this time last year. But 7.8 and 9 isn't bad. Just keep an eye on it and see when it's peaking out and getting at it's lowest...

This is the answer... When alk is in range and Ph is low its because of a CO2 build up. Try opening the lid and leave a window open in the room. If you have a skimmer it will also help.

How will a skimmer help? If the thought is that it will inject air into the water, then it will not help.

It will help by the fact it is injecting air into the water. If the tank has poor surface movement you'll need to provide another method for gas exchange. Like I said, if this is not the problem then open a window.

Unless I am thinking about this wrong, you will be injecting the same air that's causing the CO2 problem with the tank - the reason why you have C02 build up. Thats why they say to do the airstone test outside your house and then again inside your house. Also why opening a window helps. Unless you run an airline from the outside to the skimmer, this will not work.

+1... you either run an airline or go the expensive route and get a CO2 absorber.

not sure that even an airline will do it though.. but it will probably help. I have a 10g that I've been running an experiment on and I'm still not hitting 8.2.. probably 7.9 at best.. i used the biocube skimmer to run an airstone on and have the pump sitting outside on my patio. The skimmer works great as a way to control the salt creep, but that's all it does I do have quite a bit of surface flow from the AC70 so maybe it is negating whatever is brought in from the outside.. also I don't think there is much flow going through the skimmer.. so that could also be cause.

Do you have a fuge?? If so, running the lighting to the reverse from your tank lighting can help.

I had a similar situation with too much CO2 saturation getting to my tank as I touched on above. My pH was a scary 7.51 by night, and barely 7.8 by day. My alk was around 4.3dKH, also scarily low!! I dosed the alk part of B-Ionic and slowly brought my alk up. As I did this my pH gradually rose too till I was hitting almost 8.1 by day and 7.8 by night. I wouldn't sweat with 7.8 pH since my tank survived for probably months at a near 7.5 pH most nights. But you definitely want to get the pH up for sure!! I tried running an airstone pulling air in from outside to no avail nor did an open window next to the tank seem to help. Reverse fuge light schedule I tried for a couple nights didn't help much (though for most people it does help). In your case, you said your alk is normal though, so I'm not sure the same method I did would work for you since it requires dosing alk. Are you positive your alk level is normal??