Lion-o
Member
Hello!
I am battling a nitrate issue in my 300 gallon fish only tank. Nitrates are testing as high as my test kit will go (160ppm). I am not sure on my weekly growth as I haven't tested in a while, I admittedly got lazy with a happy tank. I am not new to the hobby - the tank is about 10 years old now and I haven't done a water change in a couple years. Nuisance algae died off and P04/N03 were doing good previously from vodka dosing alone. I do have some fuzzy purple looking algae (not sure on species), but not sure if that is an issue or not. I dose 19mL vodka a day (which seems like a lot to me). It wasn't until I lost a couple fish that I started doing a full panel and found this out. At that point I measured:
0 ammonia
0 nitrites
160+ppm nitrates
2.2 phosphates
So far what I have done is a 50gallon WC (16%). I blasted the rocks with a powerhead and did a gravel vac, and cleaned out the free debris in the sump.
Then I had a service come and do a ~160gallon water change (~50%), which cost me a pretty penny ($270). I tested a day later and nitrates still 160+ppm. I plan to test phosphates again, but I ran out of reagents for my hanna checker and need to order some more.
I have cut feedings down by half, plus have 2 less fish now producing nitrates.
I have an octa 205i skimz internal skimmer. Supposedly it's rated for up to 500gallons, so I believe it is already oversized for my tank. I do have a difficult time dialing it in to where it needs to be though.
I have a 40g reef tank in the same room that is thriving. I do 5gal weekly water changes there, all tests are good. It's just another beast entirely to do meaningful water changes on the 300gal. Looking for inspiration or advice.
I use RO/DI water only in both tanks.
I would like to do more massive water changes, but concerned with the cost and it possibly not solving my issue. I would also love to replace my sump, but it's barricaded in there pretty well by support beams so it would take some real surgery to get a new one in ($$). I might be able to cut two holes in the side walls, replace with a cabinet door, and then slide a brand new one with new plumbing. I wonder if I should reduce the vodka dosing or increase it. I have thought about buying an XPORT-NO3 brick (or 2) but I think it might be the same thing as the ceramic media I already have in the tank. Also read about a biodenitrator which sounds like it could help.
This weekend I plan to do another gravel vac (16% WC), do a full rinsing of my ceramic media, empty out my ATO reservoir and clean with vinegar (over time that thing always develops a thin slime, not sure what that is), and just clean out my dual carbon reactor for good measure. I will test again after all that and post an update.
I've also included some pics
I am battling a nitrate issue in my 300 gallon fish only tank. Nitrates are testing as high as my test kit will go (160ppm). I am not sure on my weekly growth as I haven't tested in a while, I admittedly got lazy with a happy tank. I am not new to the hobby - the tank is about 10 years old now and I haven't done a water change in a couple years. Nuisance algae died off and P04/N03 were doing good previously from vodka dosing alone. I do have some fuzzy purple looking algae (not sure on species), but not sure if that is an issue or not. I dose 19mL vodka a day (which seems like a lot to me). It wasn't until I lost a couple fish that I started doing a full panel and found this out. At that point I measured:
0 ammonia
0 nitrites
160+ppm nitrates
2.2 phosphates
So far what I have done is a 50gallon WC (16%). I blasted the rocks with a powerhead and did a gravel vac, and cleaned out the free debris in the sump.
Then I had a service come and do a ~160gallon water change (~50%), which cost me a pretty penny ($270). I tested a day later and nitrates still 160+ppm. I plan to test phosphates again, but I ran out of reagents for my hanna checker and need to order some more.
I have cut feedings down by half, plus have 2 less fish now producing nitrates.
I have an octa 205i skimz internal skimmer. Supposedly it's rated for up to 500gallons, so I believe it is already oversized for my tank. I do have a difficult time dialing it in to where it needs to be though.
I have a 40g reef tank in the same room that is thriving. I do 5gal weekly water changes there, all tests are good. It's just another beast entirely to do meaningful water changes on the 300gal. Looking for inspiration or advice.
I use RO/DI water only in both tanks.
I would like to do more massive water changes, but concerned with the cost and it possibly not solving my issue. I would also love to replace my sump, but it's barricaded in there pretty well by support beams so it would take some real surgery to get a new one in ($$). I might be able to cut two holes in the side walls, replace with a cabinet door, and then slide a brand new one with new plumbing. I wonder if I should reduce the vodka dosing or increase it. I have thought about buying an XPORT-NO3 brick (or 2) but I think it might be the same thing as the ceramic media I already have in the tank. Also read about a biodenitrator which sounds like it could help.
This weekend I plan to do another gravel vac (16% WC), do a full rinsing of my ceramic media, empty out my ATO reservoir and clean with vinegar (over time that thing always develops a thin slime, not sure what that is), and just clean out my dual carbon reactor for good measure. I will test again after all that and post an update.
I've also included some pics
