bio-pellets too effective

AquaPhilNJ · Jun 29, 2020

Hi,

Issue:
Seems like a dumb question even before I ask, but reducing bio-pellets somehow isn't working : - |

Since January I started using bio-pellets. Instructions say I should use 250 ml bio-pellets for my tank of 55 gallons (~210 liters). I am currently using only 30 ml (2 tablespoon) and my nitrates are always too low 0.25 - 0.75 ppm. I started dosing KNO3 (nitrates) and find within 24-48 hours nitrates return to 0.25 - 0.75 ppm no matter how much I dosed in a given day, e.g., usually 10-20 ppm.
Second, dosing KNO3 is causing phosphate to zero out.

Attempted solution:
I have been slowly removing bio-pellets for long time, there are so little remaining my reactor just looks ridiculous, as it's borderline empty. Before adding bio-pellets I required water changes; now with bp I no longer do WC. I wish to maintain my ability to not do WCs, if I remove bp I don't believe i'll have that ability.
Second, I am considering researching a way to dose Phosphate as a solution to my KNO3 dosing causing large phosphate drops. I don't think I have so many corals that they alone can eat all the nitrate, therefore suspect issue is too many bp, but already have so little of them : /

My tank's filtration is a simple sump with filter sock, large skimmer, bio-pellets reactor, positively no other filtration.

Randy Holmes-Farley · Jun 30, 2020

I'm not sure it is due to the pellets, but I'd remove them entirely.

rsumner · Jun 30, 2020

Shortly after you dose KNO3, have you tested your Nitrates and do you seem them elevated to match what you expect them to be after dosing? By doing this, it would eliminate the variable that your testing kit or procedures are invalid. Any time I'm "chasing a number" via additives, I like to test immediately before and then again immediately after dosing.

If you are interested in dosing Phosphorus with commercially available solutions (I've used Brightwell's), you'll find it is fairly inexpensive (compared to using commercial Nitrate additives). A few small drops a day will get you in the 0.02ppm range. For Nitrate additives, I made my own solution following Randy's formulas consisting of quality Potassium Nitrate since the commercially available solutions from folks like Brightwell became really expensive really fast. I would also mention that I've always found that when dosing Nitrates my Phosphate levels would always fall especially when I had an abundance of carbon available in my system as you likely do with the use of Biopellets.

As for the removal of the Biopellets: Given the fact you have no other filtration methods, I would assume either your nutrient intake is very low or you have such a healthy population of bacteria. A healthy bacteria population that is on "carbon steroids" and has its die-off and byproduct cleaned up by an effective skimmer will surprise you at what it can handle in consumption of Phosphate and Nitrate. Keep in mind, if you decide to get rid of carbon dosing and don't add some other chemical filtration, you may quickly find yourself with the complete opposite problem: high Nitrate and Phosphate.

AquaPhilNJ · Jul 1, 2020

Thank you all for your input. I will continue to monitor situation for now. My next possible action is to remove bio-pellets from reactor, by placing bp in a mesh bag and then placing that in my filter sock; reducing effectiveness, possibly not work at all. I know it takes like 8 weeks to seed bio-pellets, and maybe this will prevent the need to reseed. I did also purchase Brightwell Aquatics NeoPhos should arrive today. Wish me luck ; - ]

rsumner · Jul 1, 2020

AquaPhilNJ said:
Thank you all for your input. I will continue to monitor situation for now. My next possible action is to remove bio-pellets from reactor, by placing bp in a mesh bag and then placing that in my filter sock; reducing effectiveness, possibly not work at all. I know it takes like 8 weeks to seed bio-pellets, and maybe this will prevent the need to reseed. I did also purchase Brightwell Aquatics NeoPhos should arrive today. Wish me luck ; - ]

I wouldn't advise putting the biopellets in a sock. They need to be fluidized to prevent them from sticking together and that's going to be pretty tough to do in a sock. Good luck!!