Still have Phosphate in my RO/Di

[rk4435]

I discovered earlier this week that the PO4 problem in my tank was coming from my RO/DI unit. Water was testing at .2 right out of the unit. After troubleshooting with the assistance of the AW&I people it seemed like the only option I had left was to try a new DI resin cartridge even though the current one has only been in use for a two to three months.

With the new DI resin filter I'm at .1 Phosphate. Is there a chance that my city water is too high to completely clean? I'm basically out of options and my DT is at .2 Phos and holding despite my reactor.

 

[rk4435]

I finally realized that the high phosphate level in my tank is due to PO4 escaping my RO/DI unit.

I've done all the troubleshooting I can on my unit (membrane is fine) and installed a new DI canister today and the PO4 is still close to .2 with fresh RO/DI water. FWIW my TDS reads 195 before filtering.

After reading multiple threads on multiple sites I am seemingly have several options and have no idea which one to take.

1. Some say that RO/DI water cannot accurately show PO4 and simply trust the .000 on the TDS.

2. Others say that adding an extra DI Resin canister will capture the PO4 that is making it through the first. I have no idea how to do this and can't seem to find any good tutorials online.

3. Set up a GFO reactor on my mixing bucket to clean the water as it is mixing.

If anyone else has had a similar experience or input on the options I listed I would appreciate it.

 

[mattgee87]

wrong section

 

[atlfishes]

I've not heard that PO can't be measured in RODI water. What is your PO test kit. You need to be using a colorimeter (hanna) for accurate PO measurement. Test PO before and after your RO membrane to make sure it is effective. I'd add a maxcap filter from spectrapure and a second DI cartridge. Watch your pressure through the unit to determine if you need a booster pump.


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[skriz]

How are you testing for phosphates?

 

[dawgface]

Seth had this same problem. May want to send him a message.

 

[rk4435]

Sorry for the late reply, I've been out of town all day. I use a Seachem test kit and I get similar readings from the RO/DI, Brute mixing bucket, and display tank.

I Googled the topic and found threads on other forums where people argued that the hobbyist test kit cannot accurately test RO/DI water. I'm no chemist and won't pretend to have more knowledge than I do, I simply want to fix the problem without crashing my tank.

I have no idea how to check my water pressure since my AWI RO/DI does not have a pressure gauge. Adding another DI stage makes sense and it is an affordable fix but it could be a waste of time without proper pressure. Then again, if I have low pressure that could be the issue all together.

 

[acroholic]

Instead of an additional DI container, have you considered using a BRS media reactor with GFO instead?

 

[rk4435]

I have Acroholic. That is probably my best best given the circumstances.

 

[acroholic]

rk4435;989397 wrote: I have Acroholic. That is probably my best best given the circumstances.

I saw your initial post about having one operate on your mixing container, but if it would remove it, I would place the GFO right after your DI resin. Then you'd just swap it out as needed, and you don't have to deal with additional work of running your newly mixes SW through GFO.

Only question would be can the GFO get the PO4 in a single pass of the RODI water through it, or does it need to be circulated through the GFO a few times to get all the PO4?

 

[jennm]

Have you tested the phosphate of the untreated tap water? Just curious about that.

Jenn

 

[seth the wine guy]

DawgFace;989327 wrote: Seth had this same problem. May want to send him a message.

You can lead a reefer to PO4 free water, but you can't make em use it. Here's the semi-duplicate thread.

 

[seth the wine guy]

You should also find out what the PSI is going through your RODI. If you are too high or low, your unit won't function properly no matter what you put on it. But, IME, even a unit running at a proper flow rate/PSI will have PO4 in the end product without the use of additional "polishing" canisters. (This is using two different RODI's from two different companies.)

I bought a booster pump from AWI that has a PSI gauge that came with it. Small amount of money to invest in the big picture considering your entire tank is impacted by the quality of the water produced on the front end.

 

[rk4435]

Jen the PO4 measures 1.0 straight from the tap.

Acro, I meant adding a GFO to my mixing bucket. I'm sure that would work, but it would also be a hassel because it would mean buying another reactor and changing more media.

If I buy a pressure booster and it doesn't work I've spent a lot of money then still have to add a reactor to my mixing Brute.

I read old threads on another forum where people recommended adding another DI Resin chamber at the end or like Acro said, maybe a chamber with GFO at the end. With that option I would still need to find out about my psi, which I have to find out how to measure Seth.

Thank you all for your feedback. I've had several threads in the last year seeking help for Nitrate and PO4 problems. My fish live on half rations now but the really confusing part is that my PO4 stayed much lower a few months ago. When it spiked this time I was baffled that my RowaPhos exhausted so quickly. So anyway, the source is the problem.

 

[tonymission]

Can one run GFO on their fresh RO pre-mix? I usually have a full brute for a couple days before mixing my saltwater. Think I have a similar problem as OP.

 

[acroholic]

I have always run GFO on my reef tanks, so high PO4 has never been an issue for me. I have a Hanna ULR Phosphorus Checker, and will check my RODI for phosphates and report back.

 

[tonymission]

I just took it offline in my frag tank... Think I stripped too fast and lost color just as quickly. Already starting to get color back after three days... Will reintroduce it later with a much smaller amount of GFO

 

[rk4435]

It looks like my best bet is to get a fairly affordable water pressure gauge to check the pressure of my ro/di unit. If it is sufficient I need to add an extra stage with another DI resin (maybe one of the fancy ones) or perhaps gfo, I'm wondering if that would bubble like it should though.

If the psi is low I'm in a bit of a hard place because the booster pumps are costly and my unit is mobile not mounted, the booster would be more likely to be damaged or maybe leak prone with the weekly movement. In that case I would probably be better to add a reactor to my mixing Brute can but I can imagine that I will burn through media quickly since the source water is at least .1.

 

[seth the wine guy]

tonymission;989513 wrote: Can one run GFO on their fresh RO pre-mix? I usually have a full brute for a couple days before mixing my saltwater. Think I have a similar problem as OP.

You could, but, adding a canister of GFO on your RODI ensures 100% pass through rate/exposure to the GFO without the use of running an extra pump on your mix container. I run the <u>extra</u> DI resin after the GFO just as a last polishing. The way I look at it, the DI resin only gets exhausted as it absorbs impurities. So, whether it takes a month or a year to exhaust it, it's doing the job I want it to do either way. Running a booster pump where I can fine tune the PSI gives me the freedom to add or subtract canisters and stay within the units ideal PSI range of effectiveness.

 

[seth the wine guy]

I was getting .10 from my RODI just earlier this week. It was time to change out the filters and membrane. I am have two extra DI resins after the 5 stage. Today measured 0.00