RO Water Problems

glb · Mar 25, 2015

I just tested my RO water and this is what I got:

TDS : 7ppm
Phosphates: 0.04ppm

I got it at a LFS. I've had terrible GHA and now I think I know why. What should I do?

glb · Mar 25, 2015

NO3 was 0

joekool · Mar 25, 2015

Buy your own rodi units or you could buy a single stage DI unit to run the water through you get from LFS.

glb · Mar 25, 2015

Making a gallon or two of RODI wouldn't take much time would it?

joekool · Mar 25, 2015

No not very long.

joekool · Mar 25, 2015

If that's all you need to make than your filters will last a long time

Randy Holmes-Farley · Mar 25, 2015

glb said:
I just tested my RO water and this is what I got:

TDS : 7ppm
Phosphates: 0.04ppm

I got it at a LFS. I've had terrible GHA and now I think I know why. What should I do?

You should stop worrying about the RO water, and focus on foods. Your fish foods add tens to hundreds of times as much phosphate every day as topping off with that water.

I address that here:

Aquarium Chemistry: Phosphate And Math: Yes You Need To Understand Both ? Advanced Aquarist | Aquarist Magazine and Blog

from it:

Comparison of Food Sources of Phosphate to Other Sources
What about other sources of phosphate, like the "crappy" RO/DI water containing 0.05 ppm phosphate? A similar analysis will show it equally unimportant relative to foods.

Let's assume that the aquarist in question adds 1% of the total tank volume each day with RO/DI to replace evaporation. Simple math shows that the 0.05 ppm in the RO/DI becomes 0.0005 ppm added each day to the phosphate concentration in the aquarium. That dilution step is critical, taking a scary number like 0.05 ppm down to an almost meaningless 0.0005 ppm daily addition. Since that 0.0005 ppm is 40-600 times lower than the amount added each day in foods (Table 4), it does not seem worthy of the angst many aquarists put on such measurements. That said, tap water could have as much as 5 ppm phosphate, and that value could then become a dominating source of phosphate and would be quite problematic. Purifying tap water is important for this and many other reasons.

glb · Mar 25, 2015

I just added fish after having none for several weeks. I feed them once a day, maybe 5-6 pellets total for both. It's weird. I'm doing things like I always have but the algae is a new thing. Is that too much food?

glb · Mar 25, 2015

I have two clownfish babies.

glb · Mar 25, 2015

Randy Holmes-Farley said:
You should stop worrying about the RO water, and focus on foods. Your fish foods add tens to hundreds of times as much phosphate every day as topping off with that water.

I address that here:

Aquarium Chemistry: Phosphate And Math: Yes You Need To Understand Both ? Advanced Aquarist | Aquarist Magazine and Blog

from it:

Comparison of Food Sources of Phosphate to Other Sources
What about other sources of phosphate, like the "crappy" RO/DI water containing 0.05 ppm phosphate? A similar analysis will show it equally unimportant relative to foods.

Let's assume that the aquarist in question adds 1% of the total tank volume each day with RO/DI to replace evaporation. Simple math shows that the 0.05 ppm in the RO/DI becomes 0.0005 ppm added each day to the phosphate concentration in the aquarium. That dilution step is critical, taking a scary number like 0.05 ppm down to an almost meaningless 0.0005 ppm daily addition. Since that 0.0005 ppm is 40-600 times lower than the amount added each day in foods (Table 4), it does not seem worthy of the angst many aquarists put on such measurements. That said, tap water could have as much as 5 ppm phosphate, and that value could then become a dominating source of phosphate and would be quite problematic. Purifying tap water is important for this and many other reasons.

Thanks for the info Randy. I read the article and see what you mean. My tank crashed last summer and I've been rehabbing it after a really bad outbreak of cyano and gha admittedly due to my neglect after losing all my corals due to a temp spike. I cleaned all the rocks in the tank water and brushed off the algae with a toothbrush. Then I took the rocks out and stirred up the sandbed to remove any detritus. After I put the rocks back I did a 90% water change to start over. Before the water change the PO4 was .17ppm. After, it was 0.03ppm. This was all about 6 weeks ago. After the w/c I kept the lights off and the algae didn't come back. As soon as I turned them back on (low for blues and whites) when I got a few frags, the algae started growing again. I added the fish this past weekend. The corals are doing poorly even though my numbers are all good with the exception of nitrates at 10ppm and phosphates at 0.07ppn. I'm going to change 10% weekly for now. All of this being said, should I add a reactor to help? Sorry for being longwinded but I really appreciate your help!

Randy Holmes-Farley · Mar 26, 2015

What type of reactor were you asking about?

glb · Mar 26, 2015

Randy Holmes-Farley said:
What type of reactor were you asking about?

One for phosphates. And I'm not sure I can run one without a skimmer.

Randy Holmes-Farley · Mar 26, 2015

Sure, a GFO reactor doesn't need a skimmer and can be a good plan. There are many ways to reduce nutrients. These have more:

Nitrate in the Reef Aquarium - REEFEDITION

Phosphate in the Reef Aquarium

glb · Mar 26, 2015

Randy Holmes-Farley said:
Sure, a GFO reactor doesn't need a skimmer and can be a good plan. There are many ways to reduce nutrients. These have more:

Nitrate in the Reef Aquarium - REEFEDITION

Phosphate in the Reef Aquarium

Thanks so much! I'll read these and get back to you if I have any questions. I really appreciate being able to get a personal response from an expert!

glb · Mar 26, 2015

Ok I read both articles. From all the choices, I've read in the past that carbon dosing and Kalk are too risky in a tank that size. Is this true? Also, if I get a reactor, would you recommend phosban over Phosguard as the media? Macro algae isn't an option in my setup. I'm also still wondering if a little skimmer would help too. I have a little fun money to spend on the tank and am wondering what is the most important. A RODI unit to make my own water or the reactor and/or skimmer. The RODI unit is the most costly and since I change 1-2g/wk at most I'm wondering if it makes more sense to do the other.

glb · Mar 26, 2015

I started with a new jug of water and the TDS was 10ppm. Good grief. Should I let the LFS where I got the water know?

glb · Mar 26, 2015

I'm looking at all the filter media for the two little Fishies phosban reactor. Should I get phosban or one of the biopellets that's good for nitrates and phosphates? Also, is Kent Marine Phosphate sponge any good for lowering phosphates quickly (not a permanent solution I know)

Randy Holmes-Farley · Mar 27, 2015

glb said:
Ok I read both articles. From all the choices, I've read in the past that carbon dosing and Kalk are too risky in a tank that size. Is this true? Also, if I get a reactor, would you recommend phosban over Phosguard as the media? Macro algae isn't an option in my setup. I'm also still wondering if a little skimmer would help too. I have a little fun money to spend on the tank and am wondering what is the most important. A RODI unit to make my own water or the reactor and/or skimmer. The RODI unit is the most costly and since I change 1-2g/wk at most I'm wondering if it makes more sense to do the other.

What size tank?

i prefer GFO (any quality brand) over aluminum oxide media (such as Phosguard).

glb · Mar 27, 2015

Randy Holmes-Farley said:
What size tank?

i prefer GFO (any quality brand) over aluminum oxide media (such as Phosguard).

It's a 12g nano

Randy Holmes-Farley · Mar 27, 2015

You'd need a very slow pump to use limewater in a nano, but a dosing pump might be fine.

Using so little water, it will take a long time with an RO/DI to pay back the cost of buying water.

I might consider a reactor with GFO and maybe also GAC in it, although something like Chemipure elite might be a less capital intensive method.