Can anyone give me any ideas to solve a problem I have? I started using bio-pellets a while ago to get rid of high nitrates and phosphates. This worked like a charm for the nitrates (they went from over 20ppm to 0 in about 5 weeks and have stayed that way ever since). They were less successful with Phosphates. They did reduce them (from 2.0 ppm to less than 1 ppm) but then they stalled. I understand that this is because the denitrifying bacteria established by any form of carbon dosing (like bio-pellets) consume more nitrates than phosphates and so once the nitrate level reaches 0, the reaction stops. I have heard of some guys actually adding nitrates at this point to keep the phosphate reduction going. I did not do this. Instead I started running GFO about 15 days ago. This reduced the phosphate level quickly to O.25 ppm but again the reduction has stalled. It just won't go lower. I have checked my source water I use for changes (RO/DI) and it is 0. I change water at least twice a week (about 30 gallons each time). My tank is 125 gal with a 55 gal sump. I estimate that accounting for rock displacement etc I have about 115 gallons of water between the tank and sump. I am using 150 grams of GFO in a reactor. Does anyone have any ideas about this? How do I get rid of the rest of these phosphates?
Phosphate problem
- Thread starter Bosco
- Start date
Help Support Reef Aquarium & Tank Building Forum:
blk822822
It's only money, RIGHT?
How long has your tank been setup? And how old is the rock, did it come from someone elses tank? I have read that rock can absorbe phos. and nitrates and after awhile they cant hold any more and it starts getting released back into the tank water. Just what I have read. I used to vodka dose and that worked great untill the levels got so low my coriline algae , xenia, and some other soft corals started to go away. The SPS loved the super clean water, but some stuf didn't, so I stopped dosing.
My tank has been up for about 4 years. I have had all the live rock since the start. It is possible that phosphate has accumulated in my rock and sand and is now leaching out, since the level in my water is down because of the GFO. If this is the case I guess I'll just have to wait until the leaching stops and is all absorbed by the GFO
blk822822
It's only money, RIGHT?
Was your tank running for along time with high phos. and nitrates?
Some flake food have high phos. also, what foods do you use?
Some flake food have high phos. also, what foods do you use?
Yes, my tank had high nitrates and phosphates for a couple of years. The real problem was I had a "wet-dry" type filter as part of the sump. This was just a nitrate factory. When I removed this my nitrates dropped from about 50ppm to 20 ppm in a few days with water changes. The bio-pellets then took them to 0 where they have stayed. The phosphates didn't change that much until I started running GFO. I feed mysis, brine shrimp (both frozen, which I thaw and rinse with RO water) and spirulina flakes. I also use "Reef Snow" and Cyclop-eeze and Reef Roids occassionaly.
Maxx
Staff Housemonkey
- Joined
- Jul 31, 2003
- Messages
- 2,935
The flake food is where your phosphates are being introduced into your tank.
How long have you been feeding flake or dried foods?
I recently discovered that the Nori I had been using had significant amounts of phosphate in it and was the initial source of it in my system.
I've cut the Nori from the menu and still have phosphate present in significant amounts in the system, (unless I run GFO).
What I strongly suspect happened is that the Phosphate from the Nori was bound to my rockwork and is slowly leaching out over time.
The way to get rid of it is to "cook" the rock by placing it in a dark, (non lighted) container for approximately 6-8 weeks with weekly water changes to the container. This will change the biological processes from light driven, (algae etc) to a bacterial driven system where the phosphate is sloughed off as debris and can be purged from the rock.
Nick
