Pea Soup.

Hi everyone,

I am having an issue with a green algae bloom in my 110 gallon reef tank. It started about 2 days ago.

I test my water every two days with an API test kit. My results on the day the algae bloom broke out, and then again today are identical:

PH: 8.3, Ammonia: 0 ppm, Nitrite: 0 ppm, Nitrate: 0 ppm, Phosphate: 0 ppm, KH: 9, Calcium: 480 ppm

I WAS using tap when I first set up my tank about 2 months ago. My phosphates built up to 0.5. A week and a half ago, I switched to RODI water and added Phos-Zorb to my sump, and my Phosphate results came down.

The only "new" factor in my tank is that I finally got a working ballast for my second MH. I had been running with only one MH functional until a little over a week ago.

Any advice? Can I just ride this out? I have had the problem before with my freshwater tanks, and the only solution was cut back on my photo period. I am reluctant to do that with corals in the tank though.

 

You are probably feeding too much, so I would cut back on that. Don't add any food for the corals either. It could also be a bacterial bloom, but it sounds more like an algae bloom. Using tap added a lot of stuff for the algae to feed on. You may just have to ride it out, maybe do a water change and let it go.

 

I don't think that feeding would be the issue. I am careful about that, only feed every other day and I have a CUC.

I guess I'll just have to let it run its course.

At least my skimmer is taking a fair amount of it out of the water.

 

Set tank up 2 months ago yes well its not ready for much more then algae ..You have a low DKH high Calcium and no mention of magnesium ?
As for the algae its going to about 2 yrs till its matured enough to have all algae problems under control and that they have ran their course if you stay on top of them.

Now the fact you ran tap water with all the stuff in it then you have to figure in time like months to remove all the nasties that the rock and sand has absorbed and will leach out for months to come .

 

Well, starting with tap was done on the advice of my lfs manager. I will have to pay penance for that. Three hail mary's and frequent water changes! ;-)

Out of curiousity, what's wrong with my dkh and calcium? I thought that 8-11 was an acceptable range. I am at 9. My calcium is at 480, or 460 depending on how blue the test tube seems. Lol

What would be better levels?

 

IMO, I don't think anything is wrong with your Ca or dkh, my dkh is always around 8. Do you have a mg test kit?

 

What the DKH and ca levels tell me is your Magnesium is not near to 1400 to 1500 ppm abd If you bump that dkh up to a solid 11 as the low and average as close as you can a 13 to 14 then you will see far less algae issues .

 

Unfortunately, I don't have an mg test kit. I will pick one up tomorrow.

After MANY searches, I found a couple of links that suggest the algae may be using up phosphates so quickly that I am getting "0" test results.

On the bright side, it is out competing all the other nuisance algae because I have none. ;D

I'm skimming wet, and that seems to be pulling a lot out.

 

You were bang on. I finally managed to get a mg test kit (none of my LFS seemed to have any). I picked up an Aqua Test mg kit today, and my mg level is 1050.

Thanks for the advice!

Hopefully the local Petsmart has mg as that is the only thing still open on a Sunday here.

How slowly should I bring up the mg level?

 

Mag can be brought up 100 ppm per day max. Go with the suggestions on the supplement you bought unless it raises your level 5-10 per day. If you are going to do a large amount per day then split it into 2 or more doses. Do not dose with and alkalinity supplement. They should be dosed at least 30 minutes apart and 12 hours would be better.