R/O vs???

[Nursemom76]

I currently use an r/o filter for my aquarium water needs and I'm wondering if anyone uses anything different or if r/o is the way to go. I get a lot of waste water and use a dionizer filter to catch the waste water. I'm curious if there are r/o filters that don't give off so much waste water. I probably have about a 1:3 ratio of r/o to waste water. I certainly have few to no tank issues by using r/o, but my husband wants to find something that doesn't waste so much. Any suggestions?

 

[bang guy]

Running a deionizer exclusively will work but that will get expensive.

You can use the waste water, it's probably cleaner than your straight tap water. Mine goes into my pool when it's not frozen. It can be used in washing machines, that's fairly common. It's drinkable too.

What do you mean by "use a dionizer filter to catch the waste water"?

 

[Nursemom76]

When I run the r/o filter, I have another single cartridge filter that the waste water runs into. I get more water out of that than the r/o filter. The small filter makes dionized water. I had just the r/o filter first but didn't like how much water it wasted. I was looking to see what other kinds of filters I could use. I've always been told r/o is what I should be using. I certainly don't want to use just tap water. I eventually want to upgrade to a bigger tank and I'll need a bigger filter set up as mine is a smaller one. My ATO tank is only 4 gallons.

 

[bang guy]

You're wasting a lot of money hooking a DI onto your wastewater line. You would actually be better off using straight DI and ignoring the RO.

This is what your setup is doing:

Sediment filter removed big particles

Carbon block is removing chlorine and other chemical contaminants

RO is purifying water to the product line

RO is concentrating impurities from 10 to 100 times more concentrated to the waste line

DI is taking the super concentrated waste from the RO and purifying it.

By using the waste water you are basically nullifying all of the work the RO did.

 

[aduvall]

You can attach a second R0 filter to the waste water. That would double your output and cut your waste in half.

So the third Cartridge in your RO system, buy another one of those, and attach a hose from the waste to it. Now you have moved from 3 gallons an hour to 6 and cut waste down from 9 gallons an hour to 6.

 

[bang guy]

Adding a second RO to the waste line will cause backpressure on the first RO and low pressure on the second making neither perform well.

In my humble opinion the two good options are:

1 - Accept that RO will waste 3 - 5 gallons of water for every gallon of product water

2 - Only use a DI filter which will need to be recharged often but produces no waste water.

 

[aduvall]

I have seen multiple videos of people adding a second filter as long as the water pressure is ok. They are even sold in some places.

 

[bang guy]

I would be happy to sell you something like that. It's not going to work right though.

Connecting RO filters in parallel will work fine and will double your output. I don't think the typical RO filter will work properly in series.

Maybe I'm off base and missing something completely. I just don't see how the second RO would work properly with 25% less pressure nor how the first would work properly with so much back pressure. Even the second would have such an overwhelming amount of impurities, how effective could it be?

Snake... you've researched RO a LOT. What's your take on running RO filters in series where the downstream RO filters the waste from the previous?

 

[aduvall]

Bang. What do you mean in parallel?

 

[bang guy]

Series is one after the other like you described.

Parallel means feeding both RO filters off the same source water.

 

[Nursemom76]

What's your favorite water filter? I have a coralife, just a small one, 24 gpd I believe. I;m thinking of looking into something different that doesn't give off so much waste water. I don't have any way to store the waste water for any other uses and would like to save water not waste it. I don't have to use my filter much, maybe every couple weeks and I only have a small ATO tank so it's not much of a big deal, but would like to know what other options there are.

 

[bang guy]

I just have a 75gpd RO/DI. We use the RO a lot to supply all of our drinking water and the DI feeds the tank as well as the ice maker. My product to waste ratio is 5 gallons of waste for each 1 gallon of product water. This it typical.

 

[snakeblitz33]

Putting the waste water of one RO membrane onto the inlet to another RO membrane would cause back pressure on the first and more TDS to be leaked into the purified water. I don't recommend to put them in series. If your looking to increase the amount produced you can hook them in parallel and an extra flush kit, but eliminating waste water is practically impossible for these units.

An alternative system that has no waste water is a Kati/ani system, which uses Seperate DI resins of an anion bed and a cation bed to filter out TDS. They do exhaust quickly but can be easily recharged.

 

[geridoc]

Running a deionizer exclusively will work but that will get expensive.

You can use the waste water, it's probably cleaner than your straight tap water. Mine goes into my pool when it's not frozen. It can be used in washing machines, that's fairly common. It's drinkable too.

What do you mean by "use a dionizer filter to catch the waste water"?

No, deionized water is not the same as or RO water. Most purification systems use a combination of both (RODI) to produce high quality water. Deionizers only remove ionized (charged) molecules. There are plenty of molecules that are missed in a DI-only system.

 

[snakeblitz33]

Yeah geridoc, most neutral molecules like herbicides and pesticides aren't filtered out by a DI unit or a Kati/ani unit. A kati/ani unit does have its drawbacks.

 

[Nursemom76]

thanks everyone

 

[snakeblitz33]

thanks everyone

Let us know what decision you made!

 

[eric b 125]

I use a Kati/Ani unit, like the one Snake mentioned in post #13. I've only had to regenerate the resins in mine about once every 6 months on a 125 gallon system and now a 200 gallon DT. "KATI ANI units produce very consistent results and they are generally acknowledged to create 99% pure water. Reverse Osmosis at best is generally rated at 98% with variability of the results. Other advantages over RO include no waste of water (which is a significant cost savings), faster processing time (380 gallons/day), does not need high water pressure to operate, and no costly replacement of pre-filters, carbon block filters, and membranes" (taken from TFG's website).

I don't think that Kati/Ani's are sold any more, though.

 

[beaslbob]

Sorry I can't help. I just used tap water.

 

[Nursemom76]

Thanks Eric. I'll keep researching. I appreciate all the input from everyone!! I don't know anyone near me who keeps SW. I've been learning as I go. Spent months reading and researching to find how I wanted to set up my tank. I've taken my time thus far and have had positive results save for losing fish here and there for various reasons. As far as tank maintenance tho,I've had lots of success with keeping the tank where it needs to be.