High Phosphate in RO/DI water with 0 TDS (1 Viewer)

[PalaciosAn]

I know a TDS meter does not measure phosphate.

So I have been battling a type of hair algae in a tank for some time now. The common species that eat algae (tangs, sea hares, etc...) do not touch the stuff. I have been melting it away with hydrogen peroxide and afterward doing a significant water change to remove some of the organics released into the water. Water changes only seem to make the algae grow quicker.

My API test seems to show everything fairly much inline PO4 for the tank <.05 and freshly mixed saltwater at 0.00.

After months of dealing with it, I decided to do an ICP test on my Aquarium, Freshly Mixed Saltwater, and my RO/DI water.

I seem to have an issue with Phosphates and Phosphorus, kind of what I figured to start with. But interesting enough my 0 TDS water that the filters and changed religiously seems to be the source of the Phosphates.

Aquarium
- P = 37
- PO4 = 0.11322

Freshly Mixed Saltwater
- P = 6.862
- PO4 = 0.02099

RO/DI
- P = 64
- PO4 = 0.19584

Surprisingly, the lowest reading came from the freshly mixed saltwater (Fritz Pro) I am not sure if they add something to their salt to reduce PO4.

So the source of the issue seems to be the RO/DI water, my inline TDS reads 0 and my handheld TDS meter reads 0.

I am not sure how to deal with the issue.
- Adding GFO to the aquarium does not make sense how the source of the problem is not coming from the aquarium (overfeeding, maintenance, etc...)

- I do not know of a filter that I can add to remove PO4 from my RO/DI unit

- I could rig a GFO reactor to my RO/DI mixing station and have it strip out the PO4 there before its used for saltwater or for topping off my tank, but this seems like a pain.

Did anyone out there have a similar issue?

I found a post from someone who had the same issue, but the post was from 2015, I sent the person a message, but they have not logged on to R2R in over two years. The post had some discussion about what it could be, but nothing was ever defined as a solution.

Several years ago I swapped out my RO / DI unit from a BRS to the Aquatic Life twist unit to make replacing the filters quicker and easier. I do not know if I had the same issue with the BRS RO / DI unit as well and did not know my guess is that I did how they were both 4 stage filters.

I tested the RO/DI water with my API test kit and the RO/DI shows a higher level of PO4 then the Freshly Mixed Saltwater using the same RO/DI water.

The ICP test is an ICP Triton test in case anyone wanted to know who did the ICP test.

ideas, thoughts, comments?

 

[steveb]

@Buckeye Hydro

What would you suggest?

 

[webster1234]

edit

 

[Cody]

That level of phosphates coming into your tank via the RO unit is really not that much concern. As Randy Holmes-Farly demonstrates, you're putting 10-100 times that amount into your tank via food alone.
Aquarium Chemistry: Phosphate And Math: Yes You Need To Understand Both

My personal experience would lead to me to question your rocks first. Where did they come from? What you should do is test your tank for phosphates like usual, but when you're collecting your water sample, scrape a little bit of the rock surface off and put it in the sample. Let it set for a little while and periodicly shake the sample. After maybe 30 minutes, run your test again. If the phosphates are higher in that test than what it would normally be for your water, then the rock is your problem.

 

[Cody]

What leads me to think this as well is the fact that your phosphates are higher in the tank than the RO water. Your tank is at .11. The fresh saltwater is .02. If you did a 20% water change then your phosphates would actually be reduced to .092 from .11. I'd bet there's something actually in the tank that's causing the issue. Like I said, I would look towards the rocks. They're probably leaching out phosphates.

 

[Unlimited Color Corals]

I run gfo as our first stage of filtration in our rodi. Why battle po4 on the tank end when you can snuff it out on the front end. We already add enough po4 from foods and other items and fish waste to sustain a healthy level.

My rodi goes like this....

Gfo
Sediment
Sediment
Carbon block
Carbon block
Chloramine carbon block
Hand packed catalytic carbon
High capacity chloramine carbon block
Ro
Ro
Standard Resin
Standard Resin
Standard Resin
Mbd 10 resin
Uv sterilization


I will put our water up against any test but I already know it is some of the purest here in Houston before I make my salt mix. We battled high po4 for a while before I sent the water off to be tested and now I test our po4 from source water on the regular.

On our new shop build out I put together a system the is more organized than our last one. Since we started out with a basic system and I added things to accommodate for the issues as I found them it was a more frankenstined system than our more thoughtful planned one. Here is a photo of our planned system minus the rodi since we are between shops.


I always battle high resin use at the old place because of extremely high co2 in the water. I have not tested our source water here yet but I am assuming it will be the same.

Sent from my SM-N960U using Tapatalk

 

[steveb]

I run gfo as our first stage of filtration in our rodi. Why battle po4 on the tank end when you can snuff it out on the front end. We already add enough po4 from foods and other items and fish waste to sustain a healthy level.

My rodi goes like this....

Gfo
Sediment
Sediment
Carbon block
Carbon clock
Chloramine carbon block
Hand packed catalytic carbon
High capacity chloramine carbon block
Ro
Ro
Standard Resin
Standard Resin
Standard Resin
Mbd 10 resin
Uv sterilization


I will put our water up against any test but I already know it is some of the purest here in Houston before I make my salt mix. We battled high po4 for a while before I sent the water off to be tested and now I test our po4 from source water on the regular.

On our new shop build out I put together a system the is more organized than our last one. Since we started out with a basic system and I added things to accommodate for the issues as I found them it was a more frankenstined system than our more thoughtful planned one. Here is a photo of our planned system minus the rodi since we are between shops.


I always battle high resin use at the old place because of extremely high co2 in the water. I have not tested our source water here yet but I am assuming it will be the same.

Sent from my SM-N960U using Tapatalk

wow...

would you sharing the micron #'s on your sediment and carbon blocks? What is Mbd 10 resin?

 

[Cody]

I run gfo as our first stage of filtration in our rodi. Why battle po4 on the tank end when you can snuff it out on the front end. We already add enough po4 from foods and other items and fish waste to sustain a healthy level.

My rodi goes like this....

Gfo
Sediment
Sediment
Carbon block
Carbon clock
Chloramine carbon block
Hand packed catalytic carbon
High capacity chloramine carbon block
Ro
Ro
Standard Resin
Standard Resin
Standard Resin
Mbd 10 resin
Uv sterilization


I will put our water up against any test but I already know it is some of the purest here in Houston before I make my salt mix. We battled high po4 for a while before I sent the water off to be tested and now I test our po4 from source water on the regular.

On our new shop build out I put together a system the is more organized than our last one. Since we started out with a basic system and I added things to accommodate for the issues as I found them it was a more frankenstined system than our more thoughtful planned one. Here is a photo of our planned system minus the rodi since we are between shops.


I always battle high resin use at the old place because of extremely high co2 in the water. I have not tested our source water here yet but I am assuming it will be the same.

Sent from my SM-N960U using Tapatalk

I've always wanted a carbon clock. Where'd you get yours?

 

[Unlimited Color Corals]

@Cody smart butt...


I use 5 micron sediment filters and the same for carbon blocks. The reason I use hand packed catalytic is because I bought 10 gallons of it and it is very small stuff and I have crap tons of it.



Sent from my SM-N960U using Tapatalk

 

[steveb]

lol...

 

[TriggerFan]

@Cody: You should take a break, let's build something like this @ my place! LOL

 

[Cody]

@Cody: You should take a break, let's build something like this @ my place! LOL

If you can piece about 20 Lego blocks together then you can build this. It's simply an issue of budget and space. RO units are all ran off of quick connect fittings and you literally plug and play. Extremely easy to set up. Just gotta buy the extra canisters.

 

[TriggerFan]

Just messing with you. I need to have my RO water tested and then I'll know what I need to add to my RODI system

 

[PalaciosAn]

What leads me to think this as well is the fact that your phosphates are higher in the tank than the RO water. Your tank is at .11. The fresh saltwater is .02. If you did a 20% water change then your phosphates would actually be reduced to .092 from .11. I'd bet there's something actually in the tank that's causing the issue. Like I said, I would look towards the rocks. They're probably leaching out phosphates.

The RO/DI level of PO4 is almost twice as high as the tank. RO/DI is .2 and the tank is .11, I contacted Fritz to try to figure out why the PO4 level drops when I mix in Fritz Pro, waiting on a reply.

I do not see the need to continue to treat the tank, I want to stop it from the source. I added a GFO reactor after the RO/DI unit, I will verify that the PO4 levels dropped but tomorrow I will dump all of the water in the RO storage and saltwater storage and start over. I dosed some PO4 removal chims today and plan to do it again tomorrow and then will do a large water change 40-50%.

The tank is over 10 years old, I can't even tell you where the rock came from at this point. The algae issue started almost a year ago, this tank does not get dose much it focuses on water changes primarily so it gets weekly water changes. About a year an a half ago I swapped my RO/DI unit from a BRS to an Aquatic Life RO unit with twist filters. I am debating going back to a BRS setup to see if it was a better quality filter, unfortunately, I sold it off already. Could be that the city water quality changed and it does not have anything to do with the RO/DI unit.

Thanks, everyone for your feedback.

 

[Cody]

The RO/DI level of PO4 is almost twice as high as the tank. RO/DI is .2 and the tank is .11, I contacted Fritz to try to figure out why the PO4 level drops when I mix in Fritz Pro, waiting on a reply.

I do not see the need to continue to treat the tank, I want to stop it from the source. I added a GFO reactor after the RO/DI unit, I will verify that the PO4 levels dropped but tomorrow I will dump all of the water in the RO storage and saltwater storage and start over. I dosed some PO4 removal chims today and plan to do it again tomorrow and then will do a large water change 40-50%.

The tank is over 10 years old, I can't even tell you where the rock came from at this point. The algae issue started almost a year ago, this tank does not get dose much it focuses on water changes primarily so it gets weekly water changes. About a year an a half ago I swapped my RO/DI unit from a BRS to an Aquatic Life RO unit with twist filters. I am debating going back to a BRS setup to see if it was a better quality filter, unfortunately, I sold it off already. Could be that the city water quality changed and it does not have anything to do with the RO/DI unit.

Thanks, everyone for your feedback.

Gotcha. I must have misread the numbers earlier. Yeah, if it's coming in that high, the issue is the water supply. I'm curious how quickly the GFO will be exhausted.

 

[Buckeye Hydro]

Silica Trap DI Resin Cartridge
Is a mixed bed DI cart with extra anion resin added. phosphate is an anion.

Is your RO membrane working well? What is your feedwater TDS, RO water TDS, and DI TDS?

Russ

 

[Cody]

Silica Trap DI Resin Cartridge
Is a mixed bed DI cart with extra anion resin added. phosphate is an anion.

Is your RO membrane working well? What is your feedwater TDS, RO water TDS, and DI TDS?

Russ

Out of curiosity, in theory, could you fill a canister with the anion resin, make it a closed loop in the tank, and use it as a GFO substitute? I wonder how well it removes phosphates compared to GFO.

 

[Buckeye Hydro]

You could, but you would blow through the capacity of the resin in a heartbeat

 

[Cody]

You could, but you would blow through the capacity of the resin in a heartbeat

Yeah, plus you'd probably be taking out some other stuff that you may not want to

 

[reefling]

If nothing is touching it, you probably have bryopsis

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