Help with Brown Algae......

Byron

There's really no evidence that the rocks are raising the hardness; while it is possible, I would suspect that if they were the pH would rise also, even if slightly, but you say it has not. Whenever I have used dolomite to raise the hardness, the pH also rises correspondingly. Of course, it is possible that your water has a sufficient carbonate hardness to act as a pH buffer. Any idea what the dGH and dKH of your tap water is?

Something else jumps out at me, your nitrates are high at 40-50ppm. While it is true that most fish can tolerate this, some cannot. And the recommendations I have seen here and elsewhere are aiming at keeping them below 20ppm. Partial water changes are the only way to do this (in a non-planted tank). And weekly pwc of 40-50% should do so. If this isn't, then I would look for the reason. Possibilities are overfeeding, too many fish for the biological balance, decaying animal/plant material. These are the usual causes.

One last comment on the light: 40 watts on a 55g for only six hours a day is very low light, and probably contributing to the brown algae. Plus the high nitrates. The rocks may have nothing to do with the algae.

Byron.

JohnnyD44

Thanks alot guys!!!!

My nitrates has only started rise when the brown algae started to appear.....they usually are in check around 15-20ppm.....I do a 30% pwc every sunday afternoon....they usually are fine.....

So the rocks might be able to stay, huh?? thats good news I guess......

If the lights are contributing to the brown algae and high nitrates....should I buy higher watt bulbs or leave the lights on longer? or both?

thanks for helping me figure this one everyone....I'm glad all my fish are healthy looking and eating great...they thank you as well...

yippee

I'm not trying to jump into your thread and steal it to answer my problems, but rather add to the conversation to see if we can get better answers on what actually triggers the diatoms.

On the two tanks i have had problems with, one of them has 1.5 watts per gallon, and the other is .75 watts per gallon. Maybe the .75 is on the low side, I'm not sure. But i would think 1.5 watts per gallon would be more than enough, would it not? And i run them for a solid 8 hours per day.

SinCrisis

my 5 gallon has 4 watts per gallon... and it has brown diatoms. Does light spectrum matter?

JohnnyD44

thats what I"m starting to gather Sin....hopefully someone will chime in again about lights and wattage

mollies

Yes it dos matter I have 4 watts gallon. And i leave my lights on for 12 hrs aday. never have any problems with that but when i ran it with 2 watts i had the bloom. Also if your filter media isnt changed reguarly then you would also get the brown diatom.

mollies

Johnny the rocks can stay i wouldnt take them out. rais you wattage and leave them on longer

JohnnyD44

so at 4 watts per gallon, I need 210 watts for my 55G tank? thats seems like overkill?

Byron

I cannot recommend this. In a planted tank I would go with 1-2 watts per gallon full spectrum max. This tank has no plants, so while you have diatoms now you will have green algae with light at a level of 4 watts per gallon, particularly with the high nitrate. Algae are plants, they need light and nutrients; when they become a problem it is because the light and nutrients are high, and the algae makes use of it.

Leaving the present lights on for a longer period seems more practical. And reducing the nutrients (nitrates are a key to this). Johnny, you mentioned the diatoms appeared with the nitrate rise--the two are clearly connected, although the latter probably caused the former, not the reverse.

Byron.

redlessi

Nt enough light can cause diatoms to grow. I agree with increasing your light and it should go away.