RODI issue

jmatt · Jan 19, 2023

So I added water to my new tank last weekend and this happened. I changed the DI filter beforehand and backwashed the RO chambers a few times during the process, but I did not swap out the two carbon filters or the initial mechanical filtration. I should have my head examined, I don't know why I didn't.

I think I've only generated maybe 150 gallons of water with the RODI unit since I got it, I assumed the canisters would last longer than that. I checked TDS several times during the process and it always read zero.

Of course, I'm hoping that I can just filter it out once I have the system running, but naturally, the hose for the Reefmat is tricking water so now I have to replace / fix that before I can turn on the pumps.

Any idea what this is? The particles were initially very small but have congealed to one another. Some in suspension, other on the floor. I have hard well water but have not experienced this before when generating water for soaking the rockwork.

jmatt · Jan 19, 2023

I gotta believe the mechanical filter is the problem. I'm usually so cautious and thorough... I just figured the filter would last longer than this.

Randy Holmes-Farley · Jan 20, 2023

Particles cannot get through the RO membrane.

This is DI water with no salt added?

jmatt · Jan 20, 2023

Randy Holmes-Farley said:
Particles cannot get through the RO membrane.

This is DI water with no salt added?

No, this has salt. Instant Ocean Reef Crystals. I was making it in batches in 20 gal Brute cans, heating and mixing in the salt with a pump, making sure each can was 1.026-ish before pumping into tank.

But I thought the same thing, how could this possibly get through 4 chambers and dual RO canisters? I'm using a BRS 150gpd setup which does not have much mileage on it.

Randy Holmes-Farley · Jan 20, 2023

jmatt said:
No, this has salt. Instant Ocean Reef Crystals. I was making it in batches in 20 gal Brute cans, heating and mixing in the salt with a pump, making sure each can was 1.026-ish before pumping into tank.

But I thought the same thing, how could this possibly get through 4 chambers and dual RO canisters? I'm using a BRS 150gpd setup which does not have much mileage on it.

It is likely precipitation of calcium carbonate. Raw salt water with high alk mixes is very prone to such precipitation.

jmatt · Jan 20, 2023

Randy Holmes-Farley said:
It is likely precipitation of calcium carbonate. Raw salt water with high alk mixes is very prone to such precipitation.

Assuming I can simply filter this out once my pump is running, what should I know about either calcium carbonate (good/bad?) or high alkalinity? If you could get me pointed in the right direction I'd appreciate it. And thanks!

jmatt · Jan 20, 2023

Hannah Checker indicates Alk of 9.4. Hmm. That doesn't seem that far out of whack.

Mperry622 · Jan 20, 2023

I always run my fresh mixed salt water through some sort of filter for this very reason... I noticed i get it more if i dump too much salt in at once. try mixing in slower if that's the case

Shirak · Jan 20, 2023

jmatt said:
Assuming I can simply filter this out once my pump is running, what should I know about either calcium carbonate (good/bad?) or high alkalinity? If you could get me pointed in the right direction I'd appreciate it. And thanks!

Why are you worried about it? You said you were adding rock soon which is just more calcium carbonate..
Many of the reef salt mixes precipitate a little from the higher alk and calcium levels. Seems to happen less for me when I just use room temperature water.

jmatt · Jan 20, 2023

Mperry622 said:
I always run my fresh mixed salt water through some sort of filter for this very reason... I noticed i get it more if i dump too much salt in at once. try mixing in slower if that's the case

Well, I was making it 18 gallons at a time (in a 20 gal Brute), heating the water to 78 and adding salt with a pump stirring it until there was none left on the floor of the Brute can. Then I measured and tweaked salt until I got it to 1.026 with a Tropic Marin hydrometer. And it took me several days... so I don't think speed was the issue.

But just out of curiosity, what kind of post RODI filter? Activated carbon?

KStatefan · Jan 21, 2023

jmatt said:
Well, I was making it 18 gallons at a time (in a 20 gal Brute), heating the water to 78 and adding salt with a pump stirring it until there was none left on the floor of the Brute can. Then I measured and tweaked salt until I got it to 1.026 with a Tropic Marin hydrometer. And it took me several days... so I don't think speed was the issue.

But just out of curiosity, what kind of post RODI filter? Activated carbon?

A sediment filter for the mixed salt water