Aquarium Algae Issues, RO/DI water with high PO4?

[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 clay-boa 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.

ideas, thoughts, comments?

[outssider]

It doesn't make much sense if you made freshly mixed salt water with your ro/di water and it came out less than your ro/di water with nothing added.....maybe a testing error....If you decide to test with your own test kit keep in mind some test kits for po4 (hanna) claim they are not accurate with fresh water.....

[PalaciosAn]

My API test kind of confirms what the ICP test is showing.

I am seeing higher levels of phosphate in my RO/DI water then the Saltwater Mixed with the RO/DI water. Before I never tested my RO/DI water because the freshly mixed saltwater was low so I did not think to test the RO/DI water.

The aquarium shows higher phosphate levels, I am assuming due to topping the tank off with RO/DI water.

Has anyone had issues with their RO/DI water showing high phosphate levels? What did you do to solve it?

[bertoni]

I don't know of a salt product that contains something like lanthanum chloride that could precipitate phosphate. I'll have to think about other possible binders. If your RO/DI contains that much phosphate, the filter likely has failed somehow. I might mix up a batch of saltwater from that very bad batch of RO, and see what happens. Have you measured some water from the tap?

[PalaciosAn]

Tested the sink water and PO4 was around .5 a different issue that I plan to address.

As for the RO/DI unit, I added a GFO Reactor after the unit. I do not want to address the PO4 levels on the tank if I can stop them at the source.

[bertoni]

The RO phase should remove a lot more phosphate than it is. I am not sure what's happening, but I'd have the filter checked. Maybe the membrane isn't seated properly, or is faulty. Well, that's assuming that the phosphate results are accurate.

[mcgyvr]

Originally Posted by PalaciosAn

Tested the sink water and PO4 was around .5 a different issue that I plan to address.

.5 what?...ppb? ppm? mg/l?

How old is your ro membrane?
What is your source (sink) water tds?
What is the tds post ro membrane?

[PalaciosAn]

.5 mg/l

The membrane was replaced on 12/14/18, I normally replace it once a year and I write the date that it was replaced on the filter so that I do not forget when it was.

Source TDS is 389

After the RO/DI unit the TDS level is 1

Most of my DI resin has changed color. Before I start to make more water I was going to replace the DI.

[mcgyvr]

Thats a lot of phosphate in your source water....
And your ro membrane should only need replacement every 3 years or so..DI stage far more frequently.. 6 months to a year depending on usage..

Im not sure your test results can be trusted as the ro rembrane should be removing the phosphates just fine.. It should be doing its job as its fairly new and seems to be working fine on tds anyways..

[bertoni]

I am not sure what's happening, either. The GFO phase after the RO/DI should cure the phosphate problem.

What units is that TDS meter giving you, and has it been calibrated?

[PalaciosAn]

The test I do at home is currently an API test, I ordered a Hanna tester to get a more accurate number.

With that said the 3 original test that I provided results where ICP test done by Triton. My much less accurate API test kind of confirm what Triton results provided. I just never tested my RO/DO water only the freshly mixed saltwater.

As far as the TDS meter I have two, one that is in line with the RO/DI unit that reads before and after and I also have a handheld one. It has been a long time since I calibrated them 2-3 years... both of them read within 1 or 2 TDS from one another. They may not be completely accurate but I do not think they are that far off.

Surprisingly, I cleaned both of the storage containers that I had, RO/DI and my mixing station. The mixing station had a ton of build up in it, I need to start cleaning it once a year.

[bertoni]

I am not sure what's happening, but I'd check some RO/DI water direct from the filter for phosphate. Maybe the phosphate is getting into the storage container in some way, although that tap level is very high.

I'm guessing that the TDS meter reads in ppm, which would be fairly normal.

[Uncle99]

.1 ppm in the aquarium is not way out of line if we use 0.05 ppm as an indicator of low phosphates.

Since with phosphates we are talking about real low low amounts, API tests are likley inaccurate. ICP tests I would rely on, but again, it doesn't take much to be on the good side or bad side of a 0.05 Level.

My phosphate in the aquarium is .1-.2 ppm, I use no GFO, and I have no algae problem and corals are growing great!

Light intensity, length and colour is more likely to cause algae than a tenth or so per million of phosphates.

[PalaciosAn]

I tested directly from the RO/DI unit after a cup full of water came out (I dumped the first cup full), I agree, the API is not accurate I just bought a Henna PO4 tester which I hope is more accurate.

Yes, TDS meter is reading in PPM

I do not know, I have never had an algae issue been in the hobby for a while, I moved about two and half years and all of the sudden tons of algae that I can't get rid of.

[bertoni]

Well, we'll see what the Hanna has to say.

[Uncle99]

Originally Posted by PalaciosAn

I tested directly from the RO/DI unit after a cup full of water came out (I dumped the first cup full), I agree, the API is not accurate I just bought a Henna PO4 tester which I hope is more accurate.

Yes, TDS meter is reading in PPM

I do not know, I have never had an algae issue been in the hobby for a while, I moved about two and half years and all of the sudden tons of algae that I can't get rid of.

I do not use cups to test TDS as the sample is so small, anything will register, results will be inconsistent.

Example, in a cup, my TDS is 14ppm and in the bucket it came from 1ppm.

When you moved, the tanks new location should not get any outside light at all.
Even small amounts of sunlight, bring algae big time as this light is strong in the yellows and reds.
I made this mistake, I thought how can a tiny bit of sunlight hurt...dummy I am....

Also, Older T5's and MH colour shift as they age and shift towards the Reds, which algae loves.

While algae can grow in even low nutrient tanks, it can not grow without light.

[Uncle99]

duplicAte

[PalaciosAn]

Agree with the TDS. I have one that is in line with the RO/DI unit when I tested PO4 directly from the RO/DI unit (not from my RO/DI) storage unit I also tested the TDS to see if maybe the inline TDS meter was way off. The one in the cup is higher but not by much. That makes me feel more comfortable that the one inline should be OK.

So my father in law has been in the same house with the same tank location (built into the wall) for over 15 years. The only thing that has changed is his RO/DI unit, which was replaced from a BRS unit to an Aqualife with Twist filters to make it easier on him to change his filters. The BRS one was a little of a challenge for him, and due to that reason, the filters did not get replaced quite as fast as they should.

I recently moved into our house (was living with my inlaw) and I have been using his mixing station and just buying the salt. This weekend I set up an old BRS RO/DI unit that I had, and I am making my water (I have well water which will be new for me). My temporary frag tank with all of my sticks from when I moved has lots of algae.

His tank was great while I lived there and was doing about 1-2 water changes a week. After I moved out, we both started to have algae issues. I assumed he was not doing water changes anymore, and that was his issue and my tank I was not sure of. While I was living with my inlaw, my tank was in front of a window (no algae) I started doing 2-3 water changes on my tank a week. Bought tons of algae eaters (fish/invertebrates) none of them touch the stuff even sea hares would not touch it (though maybe it was just that sea hare because I have never heard of a sea hare not eating hair algae I have used three different one). I have injected algae with hydrogen peroxide, and the following day did a significant water change. It kills all of the algae that came in direct contact with the peroxide, but it still comes back. Have used a few different chemicals from adding more bacteria (Dr. Time & Fritz) to adding PO4 removers (Phosphat-E, a couple of others), manually removed it many times, a significant reduction in feeding, wet skimming.

Hydrogen peroxide seems to best stuff to get rid of it, but I can only use a limited amount before some corals get mad at me and I have to concentrate in a small area, then work on another area and control the areas that I have already done.

[bshow24]

One thing that should be mentioned, you can't accurately test phosphates in ultra pure water without the use of lab grade equipment. Hobbyist grade test kits will not do it, even the Hanna meters. Your best bet is a high quality handheld TDS meter. The ICP tests should show great accuracy, and in fact they show a very low amount of phosphates in your new salt water. BUT something is causing that to rise from the .02-.03 it goes in as, to .11 down the line.

In my opinion, something in the tank is causing this rise. Possibly overfeeding, or maybe rocks leeching phosphates? Once you can figure out what is increasing the phosphates, I think you'll be able to start fixing the algae problem.