Phosphate help !!!

Ok ,i have a 125 tall mixed reef , a 40g sump , 25g fuge ,in my sump i am running a super reef octopus skimmer thats rated for a 200 gallon tank , ( in process of my 180 build ) this tank has been up for almost 1-1/2 years , i dose calcium/alkalinity and within the last month or so i started dosing vinegar
all my parameters check ok with the exception of my po4 !!! I use brs reactors with carbon and gfo , i change the gfo every 2 weeks and carbon every month with a 30 gallon water change monthly
after i change the gfo , it checks at .04/.05 as days go by it rises up to .08/1.0 i just cant seem to get my corals to grow the way they should be and keep this po4 down !!!!! With the exception of changing all my lr i dont know what to do ???????
My bio load is about 7 fish with the largest being a powder blue , i feed every other day and its not a whole heck of a lot ?? I have been fighting this for months and am just about ready to go to a fish only tank !!!!!
Someone please help me figure this out ???
My fuge has a mix of chaeto/callurpa i run 3 250w mh with 14k reeflux and 2 vho super actinics
calcium stays about 450
dkh 7-9
temp 77-80
ph 8.01-8.25
salinity stable at 1.025
nitrates 0
amonia 0
i know everyone says " well you have to find the source " excuse my french here but no **** sherlock ! If i could find the source i wouldnt be here with this post ??? Any advise i will be glad to try ???
Thanks for taking the time to read and possibly reply

 

Do you feed frozen? If so do you rinse it with RO water before you add it to the tank? Where do you get your water for top offs and water changes? Have you tested the water source for PO4?

Just some ideas to see if we can find the source.

 

yes i do feed frozen , i use rods food only , i do rinse the food but not in r/o water , gotta be honest and say i use the tap here but squeeze out as much water as possible .
I use a 3 canister r/o di unit that i just changed all cartridges within the last few months , i run 1000 gallons thru them and change , the po4 levels from that are at .01 im checking my readings using a hanna po4 digital checker and have done readings 3 and 4 times in a row ???
Thanks

 

very possibly adding po4 when you are rinsing with tap, tap can be full of phosphates. Also if you are adding po4 with you ro/di that's not good.
When you change the cartridges do you sanitize the ro unit?

Also have you tested freshly made salt water? Some batches of salt can have phosphates in them, so I would also test that.

 

hmmm well sanitize the r/o unit ? No i cant say that i have ? With what and how ? But i would think that the .01 coming from the r/o water the gfo would take care of that ? And actually as far as the salt water for water changes , no i have not checked that ? I use coralife salt mix ?
Thanks

 

If you do a search on here you will find how to sanitize it, sorry it's a long post and I'm a little lazy right now lol. Just need a few table spoons of bleach and an hour or so of your time when switching the canisters. I think AZdesertrat, has posted many times how to do it on other threads.

I would def. check the newly made salt water. I know you're only adding .01 po4 but you may be adding more when you feed and more again in your salt mix, not to mention other sources and it all adds up.

 

ok i will search here for the info on cleaning the r/o unit and any suggestions of a different salt mix ?
Thanks for all the advise

 

I don't think a new salt mix is needed unless you are unhappy with the current brand. It's not so much an issue with the brand, just the batch. There may be nothing wrong with the one you have, it is pretty rare, but I have seen it. Only a test will tell.

 

gotcha ! But a stupid question then , if its not the brand how would a batch have a higher po4 ? I mix my water in 5 gallon buckets and use 2 cups in each ? It is lower then they say i should add but for my system it keeps my salinity pretty damn stable
thanks

 

Sorry, not the batches you make, but the batches of salt from the factory.