high po3 and po4

[Alexreefer]

@Randy Holmes-Farley I have a 90 gal tank that has been running for 8 months. I recently fought cyano and dinos. I tested my water today and my po3 is at 40ppm(salifert) and phosphate is at 2.0(API) all other params are fine. Why is this? Do I not have enough bacteria. I have a 2 inch sandbed that is a year old(from an older tank) and have about 50 pounds of live rock in the tank.
I have a yellow tang, 1 inch clown, bangai cardinal, melanurus wrasse, diamondback goby. I olny have 2 coral at the moment as I lost almost all of them to dinos. 1 hammer and 1 torch. I have a skimmer rated for 30-40 gal above my tank size and have 20 liters of sera siporax. run carbon,gfo and a small refugium with cheato.

 

[Reeferdood]

I am not Randy but I will tell you that using older sand can sometimes lead to issues. Back in the day I was given a complete running setup and I was always chasing my tail trying to get parameters to stabilize. I will never do that again, for that reason alone. How much are you feeding and what are you feeding? What kind of GFO are you running and how much?

 

[Alexreefer]

I am feeding 1 quarter size of mysis every 2-3 days. I am using aquatech phosphate removing gfo and running about a cup a cup and a half in a reactor with about 150 gph flow

 

[Dkeller_nc]

I'm not sure what you mean by "1 quarter size of mysis every 2-3 days". Do you mean a circle of mysis about the diameter of a quarter? If so, and this is the typical flat-pack PE Mysis, you're probably drastically underfeeding your fish. BTW, I'm think you mean you have 40 ppm "NO3", not "pO3".

Depending on how often and how much you change your water, it's not at all unusual to see a build-up of nitrate and phosphate in tank water over time. When you see established reef tanks where the owner notes nitrates of around 5 ppm and phosphates of 50 ppb, realize that doesn't happen all by itself. And as you've noticed, you don't control those parameters by underfeeding your fish and (usually) solely with water changes.

Instead, you need to do one of two things, or a combination of both, as an export mechanism. The first choice would be encouraging bacterial growth with some form of carbon dosing. That can take the form of vinegar/vodka additions to the tank water, or it can take the form of so-called "solid carbon dosing" in the form of a bio-pellet reactor. This will encourage the growth of bacteria, which your skimmer will then remove, resulting in lower nitrate and phosphate in your water. Since your nitrates are so high, I would caution you that you should start very conservatively with vinegar dosing if this is the route that you choose. In a 90g tank, I would start at 4mL of vinegar per day for a week, only adjusting upward after you've ensured that you're not going to get a severe bacterial bloom, which could make your tank cloudy and adversely affect your fish from lower oxygen levels. Note this is far below the typical "starter" dose of vinegar for your tank size.

The other alternative would be to start a refugium with macroalgae to consume the excess nutrients. This might be as easy as adding a light to your sump and adding some chaetomorpha algae, or as complicated as setting up a small auxillary tank connected to your main DT. Yet another option is to add a separate "algae reactor", such as the ones made by Pax Bellum, Skimz, and (soon) Tunze.

Finally, there is a third way, which is a dedicated sulfur or coil-type denitrator reactor. I don't recommend those unless you're an advanced aquarist. These types of reactors rely on anaerobic bacterial growth in a partially anoxic environment. If you're not careful, you can produce hydrogen sulfide from these types of reactors, which can nuke your whole tank in a matter of hours. In contrast, the first two methods are relatively safe.

 

[Alexreefer]

I'm not sure what you mean by "1 quarter size of mysis every 2-3 days". Do you mean a circle of mysis about the diameter of a quarter? If so, and this is the typical flat-pack PE Mysis, you're probably drastically underfeeding your fish. BTW, I'm think you mean you have 40 ppm "NO3", not "pO3".

Depending on how often and how much you change your water, it's not at all unusual to see a build-up of nitrate and phosphate in tank water over time. When you see established reef tanks where the owner notes nitrates of around 5 ppm and phosphates of 50 ppb, realize that doesn't happen all by itself. And as you've noticed, you don't control those parameters by underfeeding your fish and (usually) solely with water changes.

Instead, you need to do one of two things, or a combination of both, as an export mechanism. The first choice would be encouraging bacterial growth with some form of carbon dosing. That can take the form of vinegar/vodka additions to the tank water, or it can take the form of so-called "solid carbon dosing" in the form of a bio-pellet reactor. This will encourage the growth of bacteria, which your skimmer will then remove, resulting in lower nitrate and phosphate in your water. Since your nitrates are so high, I would caution you that you should start very conservatively with vinegar dosing if this is the route that you choose. In a 90g tank, I would start at 4mL of vinegar per day for a week, only adjusting upward after you've ensured that you're not going to get a severe bacterial bloom, which could make your tank cloudy and adversely affect your fish from lower oxygen levels. Note this is far below the typical "starter" dose of vinegar for your tank size.

The other alternative would be to start a refugium with macroalgae to consume the excess nutrients. This might be as easy as adding a light to your sump and adding some chaetomorpha algae, or as complicated as setting up a small auxillary tank connected to your main DT. Yet another option is to add a separate "algae reactor", such as the ones made by Pax Bellum, Skimz, and (soon) Tunze.

Finally, there is a third way, which is a dedicated sulfur or coil-type denitrator reactor. I don't recommend those unless you're an advanced aquarist. These types of reactors rely on anaerobic bacterial growth in a partially anoxic environment. If you're not careful, you can produce hydrogen sulfide from these types of reactors, which can nuke your whole tank in a matter of hours. In contrast, the first two methods are relatively safe.

Yes, 1 circle the size of a quarter. Should I feed every other day? and yes NO3 I have started dosing vinegar Monday at 3 ml every day Just bumped up to 4 today. Will go slow. Also just set up my refugium again as I discontinued it.

 

[Dkeller_nc]

From a fish health perspective, I'd suggest that you feed your fish every day, and better yet, twice a day. In general, one doesn't usually manage nutrients by sacrificing fish nutrition in the name of managing nutrients in the tank water, though you don't want to really overfeed the fish either. To give you an idea, I generally feed about 15-20 mysis shrimp to my tank's inhabitants twice a day. Those inhabitants are a smallish half black/eibli angel, a leopard wrasse, and 6 blue-eyed cardinals. Other non-fish inhabitants that are also getting targeted are a fire shrimp and a striped serpent star. Multiple hermits and emerald crabs clean up any leftovers, though almost all of what's put in is consumed within a minute.

Also note that drop-type tests for phosphate aren't very accurate. A better choice would be one of the Hanna Checker phosphate meters, though you could wait a bit on that until you have the general nutrient content of the water under control.

What's your water change schedule? While I think most of us wouldn't recommend massive water changes, 10% per week for the next several weeks would be a good idea, especially if water changes have been infrequent.