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Should I just pour some more food in there?


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I have posted this question in my build thread, but as no one answered, I figured I'd try a separate thread. Hope nobody minds.


The thing is, that I have had problems in my tank with red turf algae. The battle is about to be over, and I have finally beat that friggin' stuff. All through the process my parameters have shown low nutrition concentration. I haven't been keeping back on feeding, but then again have not overdone it either. I'm running both a skimmer, a GFO-reactor and an UAS which isn't really pulling out a lot atm. So I'm exporting some nutrients that way. Also I've been running bi-daily water changes, which presumably have also pulled out a little bit (what ever could have been left). All in all I see 0.0 NO3 and close to zero algae growth on the glass, which I translate into a very low PO4 as well. I have a proper test set ordered, so I will be sure soon.

Anyhow, my corals do look a bit starved out. I've been feeding Salifert coral food daily, for some time, but it doesn't really seem to be making a difference. My question thus is, if I should just keep feeding more, until I start to notice a raise in my values or the corals start to improve, or if you guys think I should take another approach?

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Are these SPS, LPS, or soft corals? What specifically looks starved about them -- less polyp extension, bleaching, tissue recession? Are you spot feeding or broadcast feeding? I assume your levels are all pretty solid given your vigorous water changes, but have you tested Ca and Alk recently? The frequent water changes could be stressing them a little. Also, even if you've dropped your NO3 and PO4 into more desirable ranges, a fast drop could anger them. They may just need time to acclimate to the reduced nutrients.


Phosphate test kits can be helpful, but they can be misleading. Your tank usually tells you when there's a phosphate problem. If you're not growing any algae on the glass, your phosphates are probably at an acceptable level. Also, a true 0 phosphate level is not healthy for the tank. Your maintenance and water change and filtration routine is very aggressive (which is understandable to fight the red turf algae), but it is possible that the phosphates are actually at levels that are too low to support healthy corals. More likely, though, your corals are probably just trying to adjust to whatever the new equilibrium is inside the tank.


Did you change your photoperiod while battling the algae? They may be trying to adjust to the changes in light, as well.


Some of my corals get a little unhappy for a few hours following a water change, so if you're doing water changes every 2 days they may be having a hard time recovering fully. A water change is obviously good for the tank, but it's a little bit of a shock for a brief period afterward.


do you happen to have any before & after pictures so we can see the corals when they looked healthier compared to now?

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Thanks for your answer! :)


It is a mixed reef tank, so that would include all of them. Colours are not very vivid and I experience rather slow growth if any. Zoas are not growing nor are my GSP. I have a little growth on my monties, but not too good colour on the digitata. Some LPS are having pretty poor PE. The reason I'm getting the phosphate test, is to be 100% sure I don't have an unwanted high phosphate level. But with the aggressive maintenance routine I would be very surprised to find it to be high. I have a feeling that it might actually rather be on the low side. That is why I think of feeding more.


Ca and Alk are pretty stable 390-410 and 7.0-7.3 respectively. And have been for a good while. I don't dose anything but 5mL og brightwell KH-8.3 every day, as I experience a drop in KH otherwise. Plan on changing to kalkwasser though, when things have fallen a

little more into their places.


I have not been able to measure any NO3 since I started the tank. It was started with very well running LR, so the little GHA I had to begin with took what was coming through the rather soft cycle, I believe. So I'm pretty confident that I have not stressed the corals out with a sudden drop.


I did not change photo period, but have actually changed the lamp a week or so ago. At that point I dropped the period by two hours to help acclimate the tank to me more powerful light. If anything the corals seem to do have done a little bit better since. At least the few SPS I have. The LPS might have paled out a tiny bit.


I think there could be a lot of truth in what you say about the too frequent water changes. I have used them to suck out dying algae, and think I'll keep that up for a little while still. But I'm sure that this does stress the corals. What I don't want to do at the same time, is to stress the corals even more by either under feeding them or bombing or suddenly raising nutrients.

I should add that my gut feeling tells me that the tank is a little starved out, since I have not been able to detect any rise in nutrients when the algae has started to die off. I would have expected that, but the algae is in decline and nutrients are still low. Hence my instinct to feed more ;)

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One of them 165 watt dimmable full spectrum LEDs from ebay. Running it on quite low power now as my old DIY LED/T5 hybrid had totally lost its mojo, and was practically reduced to 2x24watt t5's. The tank is a 30"x16" 29 gallon tank with a drop in it.

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