I added a 20 gallon refugium to my 139 gallon system 3 weeks ago. Installed a Kessil H380 and a softball size of Chaeto. The Chaeto has been getting quite lose and turning brown, it easily falls apart. Diatoms are growing on the floor and walls of the refugium like crazy, much less diatoms in the display. I know I have some silicates in my RO system and a new filter will be here tomorrow, otherwise water tests pretty good. Phosphate is 0.03 and Nitrate is about 8ppm. Added the refugium and the Kessil to get the Nitrates down. Will the diatoms kill Chaeto? Are my nutrients not high enough to support the Chaeto? Any help or suggestions are greatly appreciated.
Refugium help...I'm killing my Chaeto!
Its an RODI and the DI needs to be replaced. TDI is zero out but I know my silicates in the RODI output are high. Silicates tested at 39.48 ug/l and zinc was 0.73ug/l. New DI tomorrow night when my BRS package shows up.
mcarroll
10K Club member
Algae eat TDS, so that's not your problem....(even if it's a problem for you or the tank, it's not for the algae)
Is that sample from the tank or from the refugium? (Test the water in the refugium.)
0.03 ppm is not a lot of PO4....maybe within the error rate of the test kit so it could be literally 0.00 ppm. 0.00 ppm of PO4 is really bad if that's the case...and might indicate that those diatoms you mentioned are actually dinoflagellates.
Is that sample from the tank or from the refugium? (Test the water in the refugium.)
0.03 ppm is not a lot of PO4....maybe within the error rate of the test kit so it could be literally 0.00 ppm. 0.00 ppm of PO4 is really bad if that's the case...and might indicate that those diatoms you mentioned are actually dinoflagellates.
mcarroll
10K Club member
That's as close to zero as you need to be to call it zero. Algae dies when it starves. Dino's and other plankton can react differently and have a survival mode.
FYI, I'd take the refugium back offline. In adding it, you were solving a problem that didn't exist if nitrates were under 50 ppm. Even at that high I'd either do nothing or do water changes.
Nitrates should not be a problem....and your phosphate levels were already low, maybe even in need of a little boost (as you found out with the algae). Messing with a good thing!!
Not joking though....I'd let the chaeto die off and go back to what was working before. Simpler too. When the algae is finished dying off it'll restore the nutrient levels to what they were before too, so problem solved!! (Might still consider some added P if PO4 tests go back to what they were.)
P.S. I'd be curious to see what you get if you test samples from the tank and refugium back to back in the same round of testing.
FYI, I'd take the refugium back offline. In adding it, you were solving a problem that didn't exist if nitrates were under 50 ppm. Even at that high I'd either do nothing or do water changes.
Nitrates should not be a problem....and your phosphate levels were already low, maybe even in need of a little boost (as you found out with the algae). Messing with a good thing!!
Not joking though....I'd let the chaeto die off and go back to what was working before. Simpler too. When the algae is finished dying off it'll restore the nutrient levels to what they were before too, so problem solved!! (Might still consider some added P if PO4 tests go back to what they were.)
P.S. I'd be curious to see what you get if you test samples from the tank and refugium back to back in the same round of testing.
mcarroll
10K Club member
RATIO STUFF – N : P
BTW, depending on the organism growing, 8ppm NO3 would use up about 0.50 ppm of phosphate if allowed.
Assuming your 0.03 ppm number for PO4, your potential "P deficit" in the tank relative to the nitrate level is about 0.47 ppm of PO4.
Assuming you're growing corals too, I'd just consider getting some PO4 additve and starting a small dosing regime to balance P out with N.
At least in the short term, I'd try not to let the ratio go under the Redfield ratio of 16 : 1 (N : P).
It might even be better to keep the N : P ratio > 25 : 1.
With the current nitrate level of 8 ppm, you'd want about 0.30 ppm PO4 to hit 26 : 1. Target 0.30 ppm PO4 if you decide to dose.
Your current ratio (8 ppm : .03 ppm) is about 266 : 1.
Not really a problem on the nitrate side, like I said, but gives you another perspective on how low P is.
As you dose up P more than likely you'll see N start to fall, so don't move too fast....it might not take too much P before levels are where you want them.
BTW (II), moving too fast was kinda the problem with dropping a huge blob of macro into the tank. A small fragment might have survived. So don't make the same mistake in the other direction if you decide to add P......go slow.
BTW (III), if you were seeing N actually accumulate while P was stagnant, then that's an even stronger sign of P-starvation in the tank....even denitrification has been stalled.
BTW, depending on the organism growing, 8ppm NO3 would use up about 0.50 ppm of phosphate if allowed.
Assuming your 0.03 ppm number for PO4, your potential "P deficit" in the tank relative to the nitrate level is about 0.47 ppm of PO4.
Assuming you're growing corals too, I'd just consider getting some PO4 additve and starting a small dosing regime to balance P out with N.
At least in the short term, I'd try not to let the ratio go under the Redfield ratio of 16 : 1 (N : P).
It might even be better to keep the N : P ratio > 25 : 1.
With the current nitrate level of 8 ppm, you'd want about 0.30 ppm PO4 to hit 26 : 1. Target 0.30 ppm PO4 if you decide to dose.
Your current ratio (8 ppm : .03 ppm) is about 266 : 1.
Not really a problem on the nitrate side, like I said, but gives you another perspective on how low P is.
As you dose up P more than likely you'll see N start to fall, so don't move too fast....it might not take too much P before levels are where you want them.
BTW (II), moving too fast was kinda the problem with dropping a huge blob of macro into the tank. A small fragment might have survived. So don't make the same mistake in the other direction if you decide to add P......go slow.
BTW (III), if you were seeing N actually accumulate while P was stagnant, then that's an even stronger sign of P-starvation in the tank....even denitrification has been stalled.
Can't thank you enough for the replies, just fantastic to be able to tap into your knowledge base!!! Is there an easy way to distinguish between dino's and diatom's?RATIO STUFF – N : P
BTW, depending on the organism growing, 8ppm NO3 would use up about 0.50 ppm of phosphate if allowed.
Assuming your 0.03 ppm number for PO4, your potential "P deficit" in the tank relative to the nitrate level is about 0.47 ppm of PO4.
Assuming you're growing corals too, I'd just consider getting some PO4 additve and starting a small dosing regime to balance P out with N.
At least in the short term, I'd try not to let the ratio go under the Redfield ratio of 16 : 1 (N : P).
It might even be better to keep the N : P ratio > 25 : 1.
With the current nitrate level of 8 ppm, you'd want about 0.30 ppm PO4 to hit 26 : 1. Target 0.30 ppm PO4 if you decide to dose.
Your current ratio (8 ppm : .03 ppm) is about 266 : 1.
Not really a problem on the nitrate side, like I said, but gives you another perspective on how low P is.
As you dose up P more than likely you'll see N start to fall, so don't move too fast....it might not take too much P before levels are where you want them.
BTW (II), moving too fast was kinda the problem with dropping a huge blob of macro into the tank. A small fragment might have survived. So don't make the same mistake in the other direction if you decide to add P......go slow.
BTW (III), if you were seeing N actually accumulate while P was stagnant, then that's an even stronger sign of P-starvation in the tank....even denitrification has been stalled.
mcarroll
10K Club member
Microscope would be best. Even a toy $12 microscope like mine is totally adequate.
You can try the shake test....get some tank water and a patch of algae and skake it up until there's no sign of the patch...it's homogenized. Then let it sit...preferably under a bright light.
Dino's are motile, so the can regroup.
Other critters are not motile (or significantly less so), so they will remain homogenized.
This is still just a rule of thumb, so I'd recommend the $12 scope.
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