Calcium, ALK and lightning

[obring]

I just want to check info with you guys. I have been talking to this LFS about upgrading lights for the tank. At present it is a "fish only" 90 gal tank with about 60-70# LR. As some of you know I have a small war going on with keeping Ca, ALK and PH under control (Ca 550; ALK 3.0 mequ/l; and PH 7.8) He told me the other day that I could do no better until I ipgrade the lights becasue the lights contribute to the ecosystem something something. How true is this? Currently I have a 40 watt coralife and a 40 watt actinic on the tank.
Thanks in anticipation of responses~!

[Ironreef]

I would lower the cal to @450ppm the alk to 3.5 =/- and ph 8.0-8.3 but don't be a # chaser. I would maintain alk 3.5 and let the rest follow. The alk is the backbone. As for the lighting it doesn't contribute to the ecosystem other than feeding corals. In a fowlr it not as important. No need to upgrade until then.

[PerryinCA]

Well, I agree and disagree with Iron. In a fish only, or a fish only with live rock, pH isn't as big a deal as with a full blown reef, and the same goes for the ALK, and Ca. Not to say it isn't important, just not quite as crucial. I agree that if you bring up the Carbonate hardness, everything with settle into place.

As for the lighting, it does have an effect on the pH or a system when there are a fair amount of autotrophic (photosynthetic) animals. The reason being that the more light you give the animals, the more CO2 they consume. The more CO2 they consume, the less carbonic acid in the system (carbonic acid is simply water bound CO2). This is the reason people see more pH stability when using a reverse daylight algae scrubber or refugium.

Now, with little to no autotrophs, there is little need for concern. Even when there is a light-time pH fluctuation, it should be minimal if the buffering is taken care of (that means 'Alkalinity' to aquarists).

Also, I think you will get more respone in the Reef Section as this pertains more to that area, so I am gonna move this thread over there.

-Perry

[obring]

Thanks Perry... I already have gotten good info... you all are great!!

[golfish]

Good stuff there Perry, Nice to see you back at the key board

[Ironreef]

yeah don't be a # chaser you will stress yourself. if the alk is stable the ph should be. cal 400ppm + is good I was just suggesting ideal # for a reef. fo I probally wouldn't test especially if I did regular w/c. I only test now when I'm bored. I look at my ph meter. simple The only time I test is if someting doesn't look right. fwiw I run a reverse lighting on my alga tank and didn't notice a change with my ph. I know it's suppose to. maybe its not big enough. But my ph ranges 7.9-8.2 through out the day/night.