We have a 20g, for all intents and purposes, fully fledged nano reef 1 year old. It’s actually our coral and invert QT but lots of LR, sand, and some corals we’ve planted. We’ll give the crabs a little nori, a few pellets individually, and sometimes some coral food but no crazy feeding going on.
Despite this, for over a year now, we’ve battled nitrates with weekly 25-50% water changes. Nitrates typically didn’t really get any lower than 10, and usually pushing 25 before a water change. Despite this, corals flourish in this tank and all has been well.
Now to the point: due to life, it’s been between 2-3 weeks since the last water change. I figured the nitrates would be >25 and planned on a large water change and sand cleaning. To my shock they’re between 0-2 on salifert and not registering on my API! In the entire history of this tank I’ve never seen nitrates at that level. The phosphate test we have isn’t great but also looks pretty much zero. So what the heck happened?!
Aquarium details: bursting with corals at the moment as it’s taken longer than expected to get a new floor installed and set up our XXL 750. Conch’s, snails, crabs, pep shrimp, starfish. No skimmer, just a Tidal 75 HOB filter I clean every 1-2 months at most. Parameters I keep alk >8, Ca shoot for 430, and Mg I’ve never had to add; monitored by Apex and a doser. No hair algae but we did pick up some ulva that’s been a little invasive. By that I mean that little leaves of this thing have been popping up on the back wall and one snail shell, nothing seems to want to eat it. But we’re just talking about a countable number of 1/4-1/2” leaves on the back, nothing that should be able to consume so much nitrate (I think).
Could the decreased water changes and not cleaning the sand for longer than ever before have allowed anaerobic bacteria to flourish? Could it be the small amount of ulva? I’m a little scared at the moment to change anything in the tank (clean the filter, sift the sand, scrape the ulva off the back wall). I went ahead and did a 25% WC anyway but didn’t clean the sand. Just not sure how we should move forward with tank maintenance at the moment since the tank seems to be thriving with the less we do to it. Previously from a coral growth standpoint and now from a nutrient management perspective.
Despite this, for over a year now, we’ve battled nitrates with weekly 25-50% water changes. Nitrates typically didn’t really get any lower than 10, and usually pushing 25 before a water change. Despite this, corals flourish in this tank and all has been well.
Now to the point: due to life, it’s been between 2-3 weeks since the last water change. I figured the nitrates would be >25 and planned on a large water change and sand cleaning. To my shock they’re between 0-2 on salifert and not registering on my API! In the entire history of this tank I’ve never seen nitrates at that level. The phosphate test we have isn’t great but also looks pretty much zero. So what the heck happened?!
Aquarium details: bursting with corals at the moment as it’s taken longer than expected to get a new floor installed and set up our XXL 750. Conch’s, snails, crabs, pep shrimp, starfish. No skimmer, just a Tidal 75 HOB filter I clean every 1-2 months at most. Parameters I keep alk >8, Ca shoot for 430, and Mg I’ve never had to add; monitored by Apex and a doser. No hair algae but we did pick up some ulva that’s been a little invasive. By that I mean that little leaves of this thing have been popping up on the back wall and one snail shell, nothing seems to want to eat it. But we’re just talking about a countable number of 1/4-1/2” leaves on the back, nothing that should be able to consume so much nitrate (I think).
Could the decreased water changes and not cleaning the sand for longer than ever before have allowed anaerobic bacteria to flourish? Could it be the small amount of ulva? I’m a little scared at the moment to change anything in the tank (clean the filter, sift the sand, scrape the ulva off the back wall). I went ahead and did a 25% WC anyway but didn’t clean the sand. Just not sure how we should move forward with tank maintenance at the moment since the tank seems to be thriving with the less we do to it. Previously from a coral growth standpoint and now from a nutrient management perspective.