deionization instead of ro

[Anonymous]

I have a TDS meter.

Tap - 350
RO - 35
DI (1) - 4
DI (2) - 0

My guess is that something is still getting through enough to fuel algae.
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[sediener]

Rob,

Have you tested your output water for PO4, NO2, NH3, NO3?

- steve

 

[Anonymous]

Rob,

Have you tested your output water for PO4, NO2, NH3, NO3?

- steve

No. I do not have any phosphate or silicate kits. I have not tried the Nitrate.
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[Fastmarc]

I believe he's saying that most commonly available membranes rated for 100 GPD are typically designed for high output and tend to not have as good of a rejection rate, ie. 90% as opposed to the 98% often seen for the lower flow models. I discussed this with an RO vendor on the phone a few years ago and was told the same thing...

Yep, that pretty much sums it up.
AFAIK, all the 100 gpd RO sold to the hobby has a 90% rejuction rate. I have even seen quite a few online discussions say that the 100+ gpd are not technically RO membranes.
That said, with good prefilters (mainly to protect the RO membrane), carbon block (to break down the chlorine and chloramine), 100 gpd membrane and the standard size DI (not the small horizontal ones), you should be good to go with 350 ppm tap TDS. The only down side is the with the lower rejection rate of the 100 gpd, your DI won't last as long. I personally prefer the 75 gpd which has a 98% rejection rate.

Still, I'm not sure why with a TDS of 35 ppm after the RO, you are still getting 4 ppm from the first DI. With a new cartridge you should get 0 TDS, but it will be used up quicker than if the output from the RO was 5 ppm.
Like I said, I used to get 0 uS/cm (0 TDS) using the tap water filter below which just basically is a DI cartridge. No RO to help. If your water is bad it just doesn't last too long, maybe 50 gals.

Phosphates, ammonia and silicates will get caught by the DI, but ammonia and silicates are also the first to be given up when a DI cartridge is depleted. This is why the moment you see the TDS after the DI starting to climb, change it.

 

[Anonymous]

I dont know why either.

My real question is, If I am reading 0 TDS - What can be getting through that the RO/DI/DI is not getting that would fuel algae?
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[Anonymous]

My real question is, If I am reading 0 TDS - What can be getting through that the RO/DI/DI is not getting that would fuel algae?

If your TDS meter is accurate then your water isn't fueling the algae. There can be a lot of fuel stored up in porous rocks and that would be my guess. Any reef in the wild would become quickly overgrown with algae except for the grazers.

I have some Bubble-Shell Snails that do a good job on micro algae once they get a population explosion going - especially Turf & Hair algae. Let me know if you're interested.

 

[Ben1]

Rob, last time I saw a pic of your tank it looked pretty good to me. Some decent coralline growth and all. A little algae is normal as long as its not inch long mat covering all surfaces. I use a RO/DI/DI also and usually have close results to you in TDS. Mine runs 365-19-1-0.

 

[RobertoVespucci]

I would presume if the water passes through the DI cartridge too fast, then there is not enough time for the ion exchange to take place completely.

Q. How does Ion Exchange work?

A. The best analogy I have found is comparing the resin bead to a ball of yarn. The fuzz on the yarn strands are the exchange sites. Like the yarn, the resin bead is a long string (molecule) wrapped around itself. The exchange sites are where ions such as H+ or Na+ are exchanged for the heavy metals. The resins prefer the metals over H+ or Sodium and readily take up the metal and release the H+ or Na+. When the resin is freshly regenerated, many surface sites are available and the rate of exchange is high. As the resin sites fill up, the availability of sites decrease and the rate of exchange slows. This is why, at a constant concentration and flow rate, the leakage increases during a run. When the only sites available are deep inside the beads, the rate of exchange is slow and more metal leaks through.

 

[Anonymous]

My tank got allot worse, The algae has convered everything. It is thick and dark green. some places about 3 inches long.

I just did a WC on Monday with scrubbing and siphoning nad the tank got worse.
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[Fastmarc]

I would presume if the water passes through the DI cartridge too fast, then there is not enough time for the ion exchange to take place completely.

This was the only thing that I could think of as well, but I think he said that the pressure was 50 psi, so that should not result in too high a flow. You could be right though.

 

[RobertoVespucci]

Oh, I came up with other ideas . . . but they were all . . . CRAZY.

 

[Anonymous]

It could be phosphates in the rock itself. Perhaps harvesting the algae would allow it to use up the nutrients in the rock faster through 'forced' growth.

 

[Anonymous]

Roberto - What other ideas? If the TDS is 0 then what is left?

Righty - This is my dilema. If its the PO4 in the rocks then why doesn't every reef tank need the rocks replaced every 2 years?
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[Anonymous]

Righty - This is my dilema. If its the PO4 in the rocks then why doesn't every reef tank need the rocks replaced every 2 years?

I think it would depend on how the po4 is getting into the rocks, or how the po4 got into the rocks.

Fresh live rock seems to come in loaded with nutrients - hence the idea of 'cooking' the rock before it goes into the tank. The nutrients will come out of the rock without the cooking, but that will happen in your tank and it will take longer.

Seems to me that at least some of the 'new tank algae issues' may be from nutrients in the rock itself.

If you harvest as much of the HA as possible, you should be removing nutrients and at some point, there won't be enough to support HA growth.

People don't need to remove LR every two years or so because generally they are exporting more than they are importing, so the rock doesn't fill up again.

This is all a new theory I came up with in the last week.

 

[Anonymous]

This tank is 2.5 years old. 2 Years of algae
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[Anonymous]

Have you been pulling the algae out by hand?

 

[Anonymous]

i tried all of it.

Over the past 2 years:
switched salts 3 times
new lights
yanked the DSB
added flow
frequent WC's
large WC's
removed the rock and scrubbed
scrubbed and siphoned
turkey baster the LR
powerhead the LR
tried a tons of snails ot watch them die off
new RO/DI/DI system
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[Anonymous]

Do you have a current pic?
Where did the rock come from and how was it prepared?

 

[Anonymous]

The rock was purchased about 3.5 years ago from a few LFS's that was cured LR. When I had this in my 46G for 1.5 years it was fine. I moved all the rock and water to my 58 about 2.5 years ago. About 3 months later the algae started and has been here since. Somedays (far and few) its better but for the most part it is here.

I would hate to spend another $600-800 for new LR to see the same thing happen. Plus I dont have the $$ right now.

I dont have a pic at work I can post one on Sunday night when I get back home.
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[ZooKeeper1]

From what I have heard, and read, phosphates are incorporated into growing aragonite crystal surfaces, not just absorbed into the rock. The same reason dripping kalk decreases phosphate. I guess depending on where the rock came from they could be full of phosphates. The weak acid produced by the algae's rhizomes will liberate the phosphate for the algae to use, but otherwise it is safley locked away and undetectable.
I would add a few emerald crabs if you can, they do a great job of keeping the rocks algae free. I would try more snails as well, I wonder why yours die. How do you acclimate them?