Lighting, Green Algae and Water Hardness Question

[disccollector]

Talk about a loaded question...but here goes:
I have a 75 gallon reef that I just bought from a friend who had it for 8 years.
A few weeks ago I added some Kalwasser and the PH made a big leap from 7.7 to 8.4 because I added 2 teaspoons. I was told by the helpful folks here that it was too much at once but luckily I didn't lose anything. However, the day afterwards I had a brown powder all over my live rock and live sand. It appeared to be brown algae or diatoms. It's now two weeks later and after putting in some snails and crabs the brown stuff has come down a bit but now there is a new coating of green algae all over the glass.
Getting frustrated with this problem I tested my water with my Tetra test kit and got a ph reading of 7.7 and a Carbonate Hardness KH of 13degrees dH, which according to the test kit is very high for salt water.
So my question is, what could be causing this green algae and brown diatoms?
1. Could it be my lights? I have 3 VHO, 2 actinics and 1 full spectrum that I was told needed to be changed "soon" by the guy that sold it to me. I have no idea how bright they should be since I just bought it from him. But I read on here that if the lights start to die that the change in spectrum will cause algae blooms. Since I'm possibly changing lights what would you folks suggest I buy in terms of VHO's for leather corals and shrooms?
2. Is it the water hardness? How do I get the KH to come down...how do I soften the water. I currently run my tap water through and RO/DI unit but apparently this isn't helping the carbonate hardness.
Lastly, I'm guessing I should buy a better test kit because I currently can't test anything other than ammonia, nitrate/ite,ph and hardness...what else should I be testing to do it right?
Sorry for the long question but I'm really confused.
Thanks!

 

[aileena]

Maybe I can be of some help since I am kinda going through the same problem right now with the green hair algae...
1)If you have 3 vho's I would get two 50/50's and one actinic blue. I would also cut back a little on the amount of time you have your lights on, maybe like 7 total hours...old vho's would contribute to an algae problem since the spectrum changes on them.
2) if your kh is around 12 I wouldn't worry to much...12 is what I keep mine at all the time...just make sure your calcium levels are at around 450. Might want to cheap calc test kit.
3) For the algae problem cut back on your lights a few hours a day, beef up your clean up crew, and maybe get a UV light. I live by the UV light, but most people are indifferent towards them. If you get one make sure its strong enough and the flow rate is correct otherwise it will do nothing. It kills free-floating algae, so when you stir up the tank cleaning the glass and it floats around the uv light will kill it.
4) As far as test kits go I only test for ammonia, nitrite, nitrate, kh and calcium...Never bother to test for anything else...although lately I am interested in phosphate since it also contributes to nuisance algae.
Good Luck

 

[krowleey]

4) As far as test kits go I only test for ammonia, nitrite, nitrate, kh and calcium...Never bother to test for anything else...although lately I am interested in phosphate since it also contributes to nuisance algae.

what about PH?? hmmm i would think many would disagree with never testing anything else, mabey im wrong but there is alot of things you should test your water for depending on what you are keeping or getting.