Need phosphate advice

[Outofmyleague]

Hello, I have been battling a phosphate issue pretty much since I started my tank about 8 months ago. After the first cycle my tank dropped to .2 and refuses to budge either direction. The strange part to me being that it never goes up either even if I miss a water change. I'm new to saltwater but a long time freshwater hobbyist, so I'm no stranger to the fundamentals of phosphates. With that being said let me check off what I am or am not doing. I do 10% water change every week using RODI mixed to 1.026 with Fritz RPM (blue box). Originally got my water from LFS switched to making my own a couple months ago. I'm not overfeeding, I feed my fish once a day and they eat direct from the tip of the turkey baster to limit how much is dispersed in the water column as much as possible. I was dosing chaeto grow and reef roids once a week that stopped a couple months ago. When I first built the tank it had 1 hob with activated carbon and a 20g refugium with chaeto/DSB and 1 mechanical filter for a 40g DT. That build got me to .2 phos. I have since added a second mechanical filter and a 14x20 phospad to the refugium, as well as one small one inserted in the HOB. I started running GFO in the HOB instead of carbon from what I read having both is redundant (I do not run socks). I have added a skimmer meant for up to 150g. I have added 10lbs of mixed filter media (assorted pre-mix of different types, sizes, and materials) to my sump. I have been dosing pods for months and have a healthy colony along with plenty of CUC for DT with some very basic CUC for the refugium it stays pretty clean on it's own. I just received a media reactor today in hopes of getting better results from the GFO. The only thing I can think of I haven't tried is chemical treatments which I was trying to avoid. So my question wouldn't really be how to deal with phosphates, but where are they coming from?? I am pretty anal with my tank and I clean and maintain it regularly. there is nothing dead leeching into the water column. The only thing I don't go crazy with is exact parameters. I don't have digital checkers for everything so I can only get as close as salifert/api can get me. I test regularly though, and cross reference my results with multiple LFS on occasion to ensure accuracy. Everything besides the phos is healthy range for my set up and doesn't fluctuate much if at all. Mainly just your typical KH/PH swings which I have limited the PH swing by running a reverse light cycle between my DT and sump. The KH I just do water changes for. Any advice at this point would be helpful but I feel like it's an outside the box kind of answer.

 

[Shirak]

The rock can act like a phosphate sponge. It will absorb phosphate if the concentration is higher in the water than the rock and release it when the water concentration goes down. So it can take a while to get it where you want. .2ppm is not that bad if everything looks healthy and growing. I would ask what your nitrates are though. Sounds like you are limiting food and running a big skimmer and refugium which will suck up the limited nitrates. If NO3 is limited then algae, corals etc will not be able to utilize the PO4 in the water and reduce it.

 

[FUNGI]

what are you testing with?

IMO.....0.2 is not the end of the world, however, I do keep my tank a little dirty.....

 

[Outofmyleague]

my nitrates are almost always bottomed out at 0 i think 2/3 times it's tested at the 1-10 range. As far as severity the .2 isn't too bad on my tank. my corals are all vibrant and growing just very slowly; except my kenya tree which has been closed for weeks, and 1 of my 3 BTA's has been as well. I have had some algae issues. Cyano on set up, green bubble from a frag, and most recently green hair which I had to do a blackout for that was the only one that started to get out of control. The cyano i did a week blackout because there was nothing in the tank other than rock and sand. The bubble luckily for me was easy I had to pick it off a couple different rocks maybe 4 times over 2 weeks and went away. Also I use both salifert and api for testing phosphates but have had it checked through multiple LFS with a hannah checker and whatever chemical test kit they have and they all line up with what I'm getting. I'm trying to lower it due to the growth rate of algae and from most everything I read in the forums people seem to keep theirs closer to .02 not .2

 

[Outofmyleague]

my nitrates are almost always bottomed out at 0 i think 2/3 times it's tested at the 1-10 range. As far as severity the .2 isn't too bad on my tank. my corals are all vibrant and growing just very slowly; except my kenya tree which has been closed for weeks, and 1 of my 3 BTA's has been as well. I have had some algae issues. Cyano on set up, green bubble from a frag, and most recently green hair which I had to do a blackout for that was the only one that started to get out of control. The cyano i did a week blackout because there was nothing in the tank other than rock and sand. The bubble luckily for me was easy I had to pick it off a couple different rocks maybe 4 times over 2 weeks and went away. Also I use both salifert and api for testing phosphates but have had it checked through multiple LFS with a hannah checker and whatever chemical test kit they have and they all line up with what I'm getting. I'm trying to lower it due to the growth rate of algae and from most everything I read in the forums people seem to keep theirs closer to .02 not .2

also the nitrates could be a thing I thought 0 was good but the more I read I see people talking about keeping theirs at a low level probably something to do with the absorption you were talking about

 

[Shirak]

0 NO3 is bad... and .02 PO4 would be equally bad. good range for PO4 would be .05-.1ppm and nitrates around 15-20.. as a general guideline.

Light plus nutrients will give you algae.. and coral growth... and coralline algae. The way to control the algae you don't want like hair, film etc is a good CUC of snails, fish, maybe hermits etc that take care of it. It also helps to limit the places it can grow. New tanks have lots of surfaces for stuff like hair algae to grow. As corals get larger and coralline starts to cover rock there is less of it. and snails, fish, hermits etc will be able to keep it in check. It's a balancing act.

 

[Outofmyleague]

so to keep my nitrates at a healthy balance should I be feeding more? lessen filtration? dose nitrates? With freshwater it was simple pretty much any issue...just do a water change.

 

[Shirak]

so to keep my nitrates at a healthy balance should I be feeding more? lessen filtration? dose nitrates? With freshwater it was simple pretty much any issue...just do a water change.

I would not lessen filtration. I tend to feed heavy but having sodium nitrate on hand is not a bad plan. Frozen foods IMO will help boost your nitrates with less impact on added phosphate vs dry. You could add more fish! They will produce more ammonia which is good for the corals and will get turned into nitrates.

Sounds like you don't have a ton of corals though since you are keeping up with Alk by water changes? So maybe this whole nitrate/phosphate thing is not that major an issue, if it's mainly a fish system with a few corals??
Have a photo of the whole tank?

You asked how to reduce your phosphates though.. so it can be done with phosphate eliminating media like you are using or liquids like lanthanum chloride. Or naturally by stuff utilizing it in conjunction with nitrogen.

 

[Outofmyleague]

I would not lessen filtration. I tend to feed heavy but having sodium nitrate on hand is not a bad plan. Frozen foods IMO will help boost your nitrates with less impact on added phosphate vs dry. You could add more fish! They will produce more ammonia which is good for the corals and will get turned into nitrates.

Sounds like you don't have a ton of corals though since you are keeping up with Alk by water changes? So maybe this whole nitrate/phosphate thing is not that major an issue, if it's mainly a fish system with a few corals??
Have a photo of the whole tank?

You asked how to reduce your phosphates though.. so it can be done with phosphate eliminating media like you are using or liquids like lanthanum chloride. Or naturally by stuff utilizing it in conjunction with nitrogen.

I would like more fish. trying decide what to get. I am a little nervous because I have a little pygmy angel that's a bully to anything new. stressed my flamefin tang to death. second attempt at a flame too my first was lost to gill flukes. I like the pygmy's color and how active he is so I am not rushing to trade him in. I do feed strictly frozen food. I did nori when I had the tangs. I was also hoping to have a tank covered in coral. I have several types mostly easy "fast" growers xenia (I know), GSP, kenya tree, zoa, branching gorgonian, green monticap, and a galaxea. I also have a string of pearls macro in there. I wanted fast growers because we live in a rental and I don't know when we will buy, but eventually it will have to breakdown and move. At that point I will most likely scale up to about 200g. As far as advice I was mainly looking for the source not the treatment. I have spent many hours reading over treatment methods specifically for reef tanks. I thought I had all my bases covered to prevent high phosphate levels but this nitrate thing could definitely be a big part of it. Here is the DT and sump (diy). Had a lot more chaeto but had to toss it all due to aiptasia. Also my alk swings between 8 and 10 usually never gets above 10 if it gets that high I just do a 20% change.