Tank cycling, algae growing, too much light?

[leafyseadragon]

I started cycling my 37 gal FOWLR tank with a shrimp last Monday. I have about 12 lbs of LR, 32 lbs of base rock. Today the ammonia level was 0 (Tetratest kit), and I took out what was left of the shrimp.

I started the 65W PC light at 2 hours per day last Monday, increasing it to 10 hours per day right now. However, there are brownish blobs appearing on the LR and the base rock nearest the light.

Questions:

1. Are these the diatoms I've heard people talking about?
2. Should I decrease the hours of light?

 

[steve-s]

Today the ammonia level was 0 (Tetratest kit), and I took out what was left of the shrimp.

Are you sure the ammonia spiked and then went back down to zero in 7 days? I find that rather fast. How's the NO2?

Questions:

1. Are these the diatoms I've heard people talking about?
2. Should I decrease the hours of light?

Diatoms (brown film algae) are very common in newer tanks, I would just let in run as is. Once they have exausted the fuel sources in the tank, diatoms will die off naturally. Providing you use RO water and do not re-introduce impurites into the tank, they will not come back.

Cheers
Steve

 

[leafyseadragon]

Yes, I am sure the ammonia spiked. I checked it on Wednesday, and it was around 1. I tested it Friday, and it was pretty close to zero. I also thought that seemed odd, so I tested it again this morning. Still came up zero.

I bought the LR from the LFS, and it smelled fully cured. The rocks were out of the LFS tank for no more than 20 minutes before I placed them in my tank. Under those circumstances, I figure there would be little, if any die-off. I also dumped 3 envelopes of Cycle in the tank with the LR. Would that explain it?

I haven't checked the nitrites since last week, but I know they are nowhere near 0.

 

[steve-s]

I would think the pre-cured LR would have more to do with it that the "Cycle additive" but who knows for sure. If you've had the NO3 spike then I'd say your fine. Since you have removed the shrimp though, make sure you continue to add small amounts of food about twice a week to keep feeding the bacterial chain.

Cheers
Steve

 

[leafyseadragon]

That's one phrase which has never been quite clear to me, and I have seen this many times. What qualifies as "small amounts of food?" I have a small can of Kent Platinum Reef Carnivore, the small sinking pellets.

Should I add one pellet twice a week to feed the bacteria? Two pellets?

 

[steve-s]

In a 37 gal tank I would add about 3-4 twice a week. I have the same pellets and for the most part they are quite small.

Cheers
Steve

 

[leafyseadragon]

Thanks, Steve.