I've this asked on other forums, but I can't seem to get a clear answer. This is kind of a general algae question, not algae scrubber specific. Basically I can't seem to have any detectable nutrients in my tank. It's either zero or algae outbreak. I have a softy/lps tank and would like to keep some n03 and p04 in low levels. In this tank I'm actually carbon dosing, and whenever I cut back the dose, I just get algae in the display, no nutrients. It seems like whenever I start to raise the levels, algae in the display just sucks them up, no matter how low. Does anyone have any ideas on what to do?
I know this isn't specifically about scrubbers, but nobody can give me an answer and I figure you guys are the algae experts
The algae will always come back when your levels raise unless you got some other algae growoing somewere else, like a scrubber or something in the sump. This way you wont get algae in the display if thats what you are worried about. I would go with hair algae because nothing else comes even close to it at its effeciency for removing nutrients. I am not an expert at this so this is just my opinion.
Thanks for the reply! Heres what I don't understand: Let's say that I put in, for example, 5ppm of nitrate per day and my scrubber is working at full capacity. If a tank has a somewhat consistant n03 level of 2ppm, the ATS must be taking up around 3ppm per day. So I still have available nutrients in the water. What's stopping the algae from growing if the scrubber is working at it's limit? And if I add another scrubber (extra 3ppm/day), wouldn't that just bring the nutrient levels all the way down?
if you add another scrubber tehn the nutrients will go down thats for shure. However algae can self regulate itself sort of. It wont eat all the nutrients so it goes to starving and dies. If there are no nutrients available it will start dying and release nutrients which then it will consume. The only way to kill algae would be to get everything living out of the tank and then at some point it will die. You never heare anyone with alage scrubber that has striped the tank fron nutrients that say corals start to die, most times that hapens is either GFO or Pellets. You are right about the 2 ppm left, one would think that it should be enough so alage starts to grow in the tank but most times it doesnt happen if your scrubber is working right. You would think that anyhing left after the algae in the scrubber will be enough to feed algae at some other place. Even if you have left 0.05 ppm after the scrubber is done it should be enough for algae somwhere else. All I know is that for some reason if your scrubber is working the way it should algae doesn want to grow anywhere else. You maight have a bit here and there in the display but nothing crazy however, I don't know why. Someone that knows more about this stuff could be more help than me
Actually, that is not necessarily true. Some people have had issues with corals when the nutrient levels drop to zero or "ultra low". However, I would not conclude that nutrient levels being low are the cause of coral issues. Maybe with some, but a general blanket statement to that effect is not necessarily true. Also I wouldn't say "always"....on my personal tank, I just "let it be" and I don't even bother testing (mainly, because I don't have time) but on a few occasions when I have, after a period of overstocking and overfeeding, I might see elevated N and P but no change in tank algae issues. Actually I've never really had tank algae issues since the days of running only a UAS
before i had a scrubber i used to get bubble alge and hair algae in the tank if my phosphate went up, I dont get any with a scrubber as long as they dont go crazy high.
I don't understand this. At low levels of N and P, are the cuc and microorganisms just keeping algae under control?
I think many people correlate N and P levels to a direct indicator of a potential algae problem. I don't feel this is necessarily the case. In the case of running an algae scrubber, it's possible for algae in one place which provides ideal conditions (the scrubber) to out-compete growth that has less than ideal conditions (the tank, or certain areas of the tank). Part of this may involve a sort of "chemical warfare". I throw out a lot of "may" "possible" etc because this is what I have seen (anecdotal) and not necessarily precisely what is happening
At low levels of N&P even a tang will be enough to maybe keep your algae at bay however, if there is a better place for it to grow like algae scrubber then it will grow only there.
This hasn't been the case either in my experience. Algae grows fine in the ocean with levels near 0, otherwise there would be no herbivores. Correct my if I'm wrong: in the ocean there is an unlimited supply of near 0 nutrients compared to our tanks where its very limited. So algae can grow in very low nutrient water as long as it has a supply. This is why I don't quite understand the low but detectable nutrient strategy. No matter how low, algae should take up nitrate and phosphate (until there is none left) as it does in the ocean right?
Yes. Algae can grow in rediculously low nutrient levels. Algaevores can transport these nutrients to scrubbers etc. through detritus. There is evidence that scrubbers produce hydrogen peroxides ,which are intolerable to lower light residing algae however.(i.e. Display algal species)
it grows prety good in my tank where nitrate is undetectable and I have to dose nitrate to keep the sps happy
Interesting. I've been "experimenting" with my 40 gallon and trying to raise nutrients (always reads 0, drives me crazy). It went from nothing to algae outbreak all while testing levels of 0.
You are testing zero because the algae is eating it. Instead of trying to raise them by feeding I would suggest you dose nitrate and phosphate. Most times when you try doing it with food your phosphate goes up while nitrate is 0 since algae, bacteria and coral use more nitrate then phosphate. I would dose some nitrate first and bring it up to 0.5 - 1 ppm. If you are feeding your fish fairly well there shoud be enough phosphate to go around even if it tests 0
I forgot to say that you will also need something to outcompete the algae in your display, baisically grow algae somewhere else like scrubber or sump with caulerpa or chaeto.
