algae problem with sand substrate

[Kim Caron]

I have a 15 gallon FW tank with a sand substrate, filtered by a Fluval 204. Ph 8.2, ammonia 0, hardness 120. In the past with larger tanks lacking an undergravel filter, I have had problems with excessive hair algae. I swear by UG filters. This tank has shelldwellers and with the sand I am unable to use one. The algae is all over the sand, and I remove chunks of algae/sand on a regular basis and replace with fresh sand. It's also waving happily away on the fake plant in the tank, and I am tired of cleaning it off. I leave the lights off a lot, but there is apparently enough natural light in the room to keep the algae going. How do I control this algae? Do additives really work?

I am also concerned about anaerobic bacteria in the sand. I wonder if I should be stirring up the sand during my weekly 15% water changes? Or will that do more harm than good? I am down to two fish, had two batches of fry but all died except one. The tank has been up for about fifteen months. Thanks for any help.

[OCSupertones]

are you trying to raise the fry?

if not i would suggest a cory cat or an eel to churn up the sand...maybe an ottocinculus would be good for the algae on the plants...my otto's always did well with my live plants and algae, so i dont know why it would be different with fake plants... hth

[inxs]

Have you tested the water?

What is the NH3, NO2, NO3 and P. What kind of sand? Check or call the watercompany to see if they are adding something to the water.

If you don't have testkits your LFS will probably do it for you.

Check those things out first.

How much/often do you feed?

Once you find out what is causing the algae you can add some nitate, phosphate,etc... sponge to your filter and lower the levels of nutrients in your water.

[Kim Caron]

I am not familiar with the tests you are asking about. The sand is marine sand from my lfs. I have tested the hardness, PH and ammonia. Water is from my well.

Feeding is a problem. I have been told to feed often, but these fish won't touch the food unless it is swirling past them in the water, and I find them very difficult to feed. Probably overfeeding, judging by the algae. Yes, I would like to raise the fry, but as I said only one has made it. I feed as small amounts as I can two or three times a day.

[inxs]

NH3 - ammonia
NO2 - NitrITE
NO3 - NitrATE
P - phosphate

All of those can be linked to large amounts of nutrients built up in the tank through overfeeding, high fishload or high amounts of nutrients in the incoming water.

You should check the water in the tank and the water you are using for waterchanges for the above nutrients as that will affect algae growth.

Your light situation is also important - how much light do you have on the tank? (how many watts? How many hours per day do you keep the lights on?)

I assume it isn't bluegreen algae? You can use antibiotics to knock that out.

For regular algae growth you need to know the values first - you also need to know if the nutrients are present in your tapwater ( in which case waterchanges will not do much good).
Assuming you have high amounts of NO3 (nitrAtes) and P (phosphate) - these can both come from overfeeding , wastebuildup or be present in the water source - you should do a large waterchange (50%+) , cover the tank for 3 days (no lights) and follow with another waterchange (50%+) after that monitor your watervalues and if needed add phosphate or nitrate sponge to your filter.
Good luck

[Kim Caron]

Thanks, inxs. Love your music, by the way. I have tested for everything but nitrAtes, which I got mixed up with nitrItes, and have given more thought to the situation with the help of you and others. Have concluded that my canister filter has NOT been cleaned as often as it should. With such a light fish load I have only done it every 3 months. My other source tells me that charcoal lasts only a month then does more harm than good. He also pointed out that when I lose a batch of fry, which happened not long before the algae problems got really bad, their dead bodies go into the canister filter, there to rot and wreck my water. DUH! Stupid Kim! My only excuse is that I have always kept community tanks in the past, no fry, and any DBs get devoured before they have a chance to rot, or I have gotten them out of the tank quickly. The fry just disappeared. Out of sight out of mind, when you're a stupenagel.

So my problem is more than likely excessive nitrAtes from the dead fry. I would have tested for them but can't find my kit, it must have gotten used up. I will clean the canister filter, do a large water change, and start stirring up a portion of the sand and cleaning it on a regular basis. Now that I know it's necessary I am happy to clean the canister every month.

Thanks for the help!