Brown algae and hydrogen sulfide

[Capt Crabtabulous]

I've had a reef tank for over twenty years, but I'm so frustrated that I'm close to getting rid of it. A little background.

Fourteen years ago I set up my current 250 gallon tank. It was beautiful for at least eight years. Then I started getting brown algae on the sand and rocks. When the sand was stirred up the sand underneath was black and smelled terrible. So I broke the tank down and started over. New sand. New live rock. But after a few months the problem returned. This time I tore the tank down and put the live rock in a covered garbage can with a high flow pump circulating the water. I left the rock in there for three months. I then put a small amount of new sand (less than an inch) in the tank, new water and the rock. Now it's happening again.

My salinity is 1.023
Phosphate >.02
Ive tried running gfo and carbon but it doesn't appear to have helped. As a side note, my home gets water from a well. It goes through a sediment filter and a water softener before going through an ro/di system.

Please help me. I've loved this hobby but I'm just about out.

 

[bertoni]

I would raise the SG to 1.0264 over a period of a week or so. If there's still phosphate measurable, the GFO is shot, which can happen in a few hours. What is in the system in the way of fish and live rock? A picture might help.

 

[mcgyvr]

What type of sand used?
Pictures of the problem? (please turn blue lights off/way down for proper color rendition which is very helpful in ID pictures)
Age of current tank?
Output TDS of RO/DI?
Tested for silicates?
Reef tank or fish only?

You still having a problem with hydrogen sulfide on 1" of sand? Pics of that too..

 

[Capt Crabtabulous]

Thanks for the reply's. I'm out of town for a couple of days, but when I get back I'll get the requested info.

 

[Capt Crabtabulous]

https://photos.app.goo.gl/nQ5GfBsuvEV3waTM6

 

[Capt Crabtabulous]

I’m trying to post some pictures and not having much success. In the meantime while I try to educate myself on picture posting here are my current parameters.
Salinity: 1.023. I’m raising to 1.025 as suggested.
Phos (measured with a Hanna meter): .02
Alkalinity (measured with Salifert test kit): 9.9
TDS: 0.0
Silica: 0.0

A little more info on tank. It’s ~230 gallons with a 40 gallon sump. I have a protein skimmer in the sump and use a calcium reactor. Lately I’ve also been running some of the sump water through a carbon filter. I’ve used GFO in the past, but with my phosphate at .02 I quit using it. I only have three fish in the tank at this time. Two tangs and a chromi. Of course various snails and crabs. Oddly enough I have three acropora that are doing great in spite of the algae and hydrogen sulfide problems.

 

[Capt Crabtabulous]

Yea I know. It's upside down. It wasn't when I uploaded it:dance:

 

[Capt Crabtabulous]

 

[bertoni]

How much food is going into the system? The substrate might be fairly coarse. It's hard to tell from the photo. If so, such substrates tend to accumulate detritus over time. I had to pitch all my crushed coral.

 

[Capt Crabtabulous]

I only feed the fish half a cube of food every other day.

 

[mcgyvr]

Tried Chemiclean/Red Slime remover? That looks more like a bacteria than an algae IMO..

 

[bertoni]

How big are the cubes? I might try feeding ¼ cube per day, to even out the nutrient spikes. What is the phosphate reading? Do you mean that you always get a reading over 0.02 ppm? You might need a lot of GFO or some lanthanum chloride, if so.

 

[Capt Crabtabulous]

The cubes are about 1/2”x1/2”x1/2”. So is .02 too high for phosphates? I guess I thought that was pretty good. I could definitely go back to gfo if you think it would help.

 

[outssider]

In your first post, you said your phosphates are greater than .02 ...so that's not much help to us !... did you mean less than .02 ??

 

[bertoni]

I might try cutting back on the food for a while, too. The tank is a bit ugly.

0.02 ppm for phosphate is okay, if that's what the level is, but the growth on the rocks indicates that there's enough phosphate in the system (total) to promote algal growth. Sometimes, but not always, GFO or other phosphate control can help in such situations. It's very easy to try. Another idea might be carbon dosing: vodka or vinegar often help, too.

 

[Capt Crabtabulous]

I just rechecked my phosphates and got .05 this time. Thanks for the advice. I think I’ll get the gfo going again and look into your other suggestions. I really hope something works as I really miss my old tank��

 

[Capt Crabtabulous]

I am curious though about the hydrogen sulfide issue. Could that be related to the elevated phosphate ?

 

[bertoni]

The hydrogen sulfide is the output of anaerobic microbes in the sand. The organics and other nutrients (including phosphate) are the source. The size of the sand grains is one factor in how quick and to what extent this develops, along with the animals in the substrate.

 

[Capt Crabtabulous]

First, thank you to everyone that replied with ideas/suggestions concerning my problem. I'd like to especially thank Mcgyvr for the bacteria insight. As I've read posts and looked at pictures, I believe this is a dinoflagellate issue. I'm currently trying to learn as much as I can about the problem, but it looks like a uv sterilizer is in my future.

 

[bertoni]

A UV sterilizer might help some. That seems to vary a lot, though.