Looking for Confirmation on Softener/RO Unit Set-Up

[Drayden Farci]

Been a while since my college chemistry classes, and I've never had to mess with water chemistry before moving. A little advice is appreciated!

Just purchased a home in Florida, USA. Water is basically liquid rock, with high limestone, Ca, Fe, etc. feeding into the city water. I plan on getting a <water softener system> for the home. This system is supposed to remove Fe, hardness ions (Ca, Mg, etc.), and chlorine. It is a salt-exchange softener and will add Na to replace those ions. First question: This is a good step, but ultimately not recommended for soft-water fishes, correct?

Assuming the above is correct, I plan on adding an RO unit under the sink (any recommendations?). I plan on adding a t-split to send RO water to both a small reservoir for normal drinking, and a larger reservoir for housing enough water to perform my slight water changes (usually 15 gallons or less at one time). Once the water is through this system, it should be "better" for the fish, yes?

Now, I have been fortunate most of my life to live in an area of the US that has extremely soft water and doesn't require any sort of chemical adjustments to help Apistogramma spawn. Does straight RO water require re-mineralization for any reason? Obviously this will depend on the species (aiming for tank-bred Apistogramma sp. Abacaxis to start). The tank will be heavily "planted" with fallen palm fronds and Southern Oak leaves.

If I wanted to mix it with the softened water from the tap, it sounds like this would be fine, and potentially beneficial from a buffering standpoint, considering some old <research I found from TJudy> on the effects that pH, conductivity, and hardness have on rearing Apistogramma - the conductivity usually didn't matter as much as pH. With the RO unit and some leaf debris, the pH should drop to low 6's I imagine, which should be safe and beneficial for the fish.

 

[MacZ]

First question: This is a good step, but ultimately not recommended for soft-water fishes, correct?

If aiming for low conductivity, as is the case with softwater fish, it makes things in most cases more complicated. This is the case here. So. Yes.

Once the water is through this system, it should be "better" for the fish, yes?

Yes.

Does straight RO water require re-mineralization for any reason?

For clear and blackwater species - not at all. For most it boils down to 100% RO or distilled or rainwater + humic substances.

With the RO unit and some leaf debris, the pH should drop to low 6's I imagine, which should be safe and beneficial for the fish.

Save yes. If you really reach low 6's without adding extra humic substances is questionable though. At least a leaf litter bed and some additional humic substances will be necessary to a. get it down there, b. keep it there. Even if you do small water changes (15 gallons of what btw? What percentage is that for your tank(s)?), humic substances are removed and they also degrade over time. To keep the H+ at level it takes regular addition.

 

[Apistoguy52]

Correct.

Better, yes.

Re-mineralization, yes…to a degree. While the abacaxis will breed and rear fry in water with GH in the 10-100ppm tds range wonderfully, I like to have a baseline GH around 2dGH (30-40 ppm tds). Having some sodium, magnesium, and calcium available just makes better babies in my experience.

 

[Mike Wise]

This system is supposed to remove Fe, hardness ions (Ca, Mg, etc.), and chlorine. It is a salt-exchange softener and will add Na to replace those ions. First question: This is a good step, but ultimately not recommended for soft-water fishes, correct?

You will increase the conductivity by 2X using salt to replace other ions. This is not a good idea for softwater fish.

I plan on adding an RO unit under the sink (any recommendations?). I plan on adding a t-split to send RO water to both a small reservoir for normal drinking, and a larger reservoir for housing enough water to perform my slight water changes (usually 15 gallons or less at one time). Once the water is through this system, it should be "better" for the fish, yes?

R/O would definitely be better for softwater (= low electrical conductivity) fish.

Does straight RO water require re-mineralization for any reason?

In most cases, no. There will be enough organics in the tank that you shouldn't need any kind of remineralization, but it depends more on the nutrient needs of the plants than the fish.

If I wanted to mix it with the softened water from the tap, it sounds like this would be fine, and potentially beneficial from a buffering standpoint

Personally I think this is a poor idea. Na ions do not buffer water and you are only increasing the conductivity which is not a good idea for softwater fish.

some old <research I found from TJudy> on the effects that pH, conductivity, and hardness have on rearing Apistogramma - the conductivity usually didn't matter as much as pH.

This is not correct. Conductivity is at least as important - if not more - than pH.

With the RO unit and some leaf debris, the pH should drop to low 6's I imagine, which should be safe and beneficial for the fish.

Softwater species tend to be more adaptable to pH fluctuations, so long as it remains less than neutral pH. With proper tank management you shouldn't have any problems keeping values in an acceptable range.

Personally if I had your tap water (thankfully I don't ) I would buy an R/O unit with a reverse flush unit and run straight tapwater through it. Why waste salt to soften water only to remove it later?? Since your tapwater is so hard a reverse flush unit for the R/O membrane will make it last much longer.

 

[Drayden Farci]

15 gallons of what btw? What percentage is that for your tank(s)?

I have a 33 Long and a few smaller tanks. I generally perform frequent, smaller changes rather than infrequent, larger ones. Generally I'll pull 2 gallons out, replace it with 2 new gallons, pull 2 gallons out again, replace, etc.

Softwater species tend to be more adaptable to pH fluctuations, so long as it remains less than neutral pH. With proper tank management you shouldn't have any problems keeping values in an acceptable range.

Personally if I had your tap water (thankfully I don't ) I would buy an R/O unit with a reverse flush unit and run straight tapwater through it. Why waste salt to soften water only to remove it later?? Since your tapwater is so hard a reverse flush unit for the R/O membrane will make it last much longer.

Great, sounds good! I'm totally fine without extra trouble of remineralizing or mixing.

Thankfully you don't have my water! As far as wasting salt to soften it later - I read that it would prolong the life of the RO filters if I used softened/conditioned water rather than this liquid rock. But, I also want the softener for the rest of my house anyway, for showers, laundry, dishes, and cooking. I've been living here a few weeks and every morning I wipe salt reside off my faucet handles. I also just put in new plumbing, and while I expect them to last quite a while, the softened water will help a bit there.

Always appreciate the insight from you all. Been a while since I posted, but hopefully I'll have some Apistogramma of my own again soon.

 

[MacZ]

I have a 33 Long and a few smaller tanks. I generally perform frequent, smaller changes rather than infrequent, larger ones. Generally I'll pull 2 gallons out, replace it with 2 new gallons, pull 2 gallons out again, replace, etc.

Allright. In my experience not the best technique. A good 30-50% each week will get you more predictable and more stable waterquality. Smaller changes can cause long term build-ups of waste products we can't test for, and hormones. And those can be detrimental to health, spawning activity and growth rates.

I read that it would prolong the life of the RO filters if I used softened/conditioned water rather than this liquid rock.

Whereever you read that, check their sources. Also the smaller the ions in molecule or atom weight, the likelier the membrane in an RO unit doesn't filter them out. People report problems with sodium, potassium and copper not being properly removed.

But, I also want the softener for the rest of my house anyway, for showers, laundry, dishes, and cooking. I've been living here a few weeks and every morning I wipe salt reside off my faucet handles

After the softener is installed it will be salt. Right now it's limescale.
But that's exactly the point. These things reduce hardness the way manufacturers of household appliances define it: Calcium, Magnesium and Calcium-Carbonate.
So the water prolongs the life of your washing machine and the coffee maker, but for aquaria it's rubbish.

Always appreciate the insight from you all.

You're welcome!

 

[dw1305]

Hi all,

Water is basically liquid rock, with high limestone, Ca, Fe, etc. feeding into the city water.

Could you use rain water? I have hard tap water (about 17 dGH / 17 dKH) but I've always used rain water, without any problems. We have an ion exchange water softener for showers etc. and it gets through a lot of salt.

I know it isn't legal to intercept rain-water in some USA states, but I'm guessing it rains a lot in Florida? So you don't have the same issues.

cheers Darrel

 

[Drayden Farci]

Could you use rain water? I have hard tap water (about 17 dGH / 17 dKH) but I've always used rain water, without any problems. We have an ion exchange water softener for showers etc. and it gets through a lot of salt.

I know it isn't legal to intercept rain-water in some USA states, but I'm guessing it rains a lot in Florida? So you don't have the same issues.

Yes, and I have a big rain barrel that's currently sitting full of water. That said, it hasn't rained for probably a month now. Between May and October it rains enough to provide water for changes, however I'm hesitant to use it. Would I need to run it through any filters prior to using? I don't know what has/hasn't been introduced to the barrel, including squirrel feces, etc.

Allright. In my experience not the best technique. A good 30-50% each week will get you more predictable and more stable waterquality. Smaller changes can cause long term build-ups of waste products we can't test for, and hormones. And those can be detrimental to health, spawning activity and growth rates.

Noted.

Whereever you read that, check their sources. Also the smaller the ions in molecule or atom weight, the likelier the membrane in an RO unit doesn't filter them out. People report problems with sodium, potassium and copper not being properly removed.

Noted as well, and fair point on molecule size.

After the softener is installed it will be salt. Right now it's limescale.
But that's exactly the point. These things reduce hardness the way manufacturers of household appliances define it: Calcium, Magnesium and Calcium-Carbonate.
So the water prolongs the life of your washing machine and the coffee maker, but for aquaria it's rubbish.

Yes, and that's sort of the confirmation I was looking for based on my research - House=Good, Aquarium=Bad. Considering I want to soften the entire house, I will have to live with the risks of the Na getting through an RO filter, I suppose.

 

[MacZ]

Yes, and I have a big rain barrel that's currently sitting full of water. That said, it hasn't rained for probably a month now. Between May and October it rains enough to provide water for changes, however I'm hesitant to use it. Would I need to run it through any filters prior to using? I don't know what has/hasn't been introduced to the barrel, including squirrel feces, etc.

If you collect it in an open container it's probably best to test it and to filter it meachnaically. If you expect contamination from birds or rodents it's a bit different. But just technically rainwater would definitely be an option, at least to a degree.

Yes, and that's sort of the confirmation I was looking for based on my research - House=Good, Aquarium=Bad. Considering I want to soften the entire house, I will have to live with the risks of the Na getting through an RO filter, I suppose.

You could split the pipe in front of the softener and as a bypass. Many people do that when they install a softener. It is also not said that the Na will for sure go through the filter. Seems there are differences.

 

[Drayden Farci]

You could split the pipe in front of the softener and as a bypass. Many people do that when they install a softener. It is also not said that the Na will for sure go through the filter. Seems there are differences.

Just to follow up, most of the sources I found have stated to place the RO unit after the water softener to prolong the life of the membranes. I only found one person who postulated that the smaller ion size would have a negative effect overall. I could easily add a bypass as well, as the plumbing is easily re-arranged, but it seems like most softening companies and aquarists prefer putting the RO unit after everything else. Definitely a good thought experiment.

Link 1
Link 2
Link 3

 

[Mike Wise]

This why I recommended that you get a back-flush system for your R/O unit. It uses R/O water to back-flush the membrane. Once you have the unit it needs no other changes.

 

[Drayden Farci]

This why I recommended that you get a back-flush system for your R/O unit. It uses R/O water to back-flush the membrane. Once you have the unit it needs no other changes.

I did some very brief research and didn't find much, but I haven't revisited. I'm planning to get an RO unit from the same person selling the softener, so I'm not sure of the model, but if the back-flush technology can be applied to any unit, I'm all for learning more. Do you have any links to other research? I'll check the forum later tonight.

 

[MacZ]

Just to follow up, most of the sources I found have stated to place the RO unit after the water softener to prolong the life of the membranes.

Well, in comparison to liquid rock, of course it makes sense to install a RO unit behind the water softener to have the membrane work longer. The back-flush valve does that, too. But the membrane-lifetime isn't my point. It's just the possibility that with a cheap or more permeable membrane in the unit, the conductivity might be higher still, requiring another stage in the form of a DI. A separate line parallel to the softener would eliminate that possibility. And as Mike said, with a back-flush valve the membrane is still saved.
Most RO units are modular and compatible with each other, so single parts (like additional filter stages), kann always be added or removed without any trouble. A back-flush valve is available in Europe for 10-20€, so it's safe to say it's also available at about that price range to you as well.

 

[Mike Wise]

Back-flush equipment can be added to most R/O units. This site is one of several sites that shows how:

 

[Drayden Farci]

Back-flush equipment can be added to most R/O units.

When would the flushing occur?

- Before or After using it to fill a holding tank?
- Before or After using it to fill a glass of water?

When is the "optimal" time to flush, and would flushing less frequently offset the "advantages" of using previously-conditioned water that is free from everything except Na?

I may have two holding tanks for the system, with one leading to a faucet or fridge line for drinking water and the other to a larger tank that can be used for aquarium water.

 

[Apistoguy52]

When would the flushing occur?

- Before or After using it to fill a holding tank?
- Before or After using it to fill a glass of water?

When is the "optimal" time to flush, and would flushing less frequently offset the "advantages" of using previously-conditioned water that is free from everything except Na?

I may have two holding tanks for the system, with one leading to a faucet or fridge line for drinking water and the other to a larger tank that can be used for aquarium water.

I believe the generally accepted “best practice” is to flush the membrane for a few minutes upon startup. Given the hardness of FL water, additional “flushing” after, and at regular intervals during the product water run would probably add life to the membrane. Couple minutes (2) here and there should save you some money over the long run.

 

[MacZ]

- Before or After using it to fill a glass of water?

In case I got you correctly there: Don't drink pure RO. It's chemically almost identical to distilled water. Using it for coffee, tea, cooking - all fine, but better don't rely on it as your drinking water. For adults a glass here and there is ok, as a longterm main source of drinking water this can have effects e.g. on your kidneys.
Plus, it still takes about 5 minutes and uses 5-10 liters of water that go to waste, so doing this for every glass of water is quite excessive.

- Before or After using it to fill a holding tank?

Yes, before and after producing bigger amounts is the usual practice. Depending on the source water inbetween might be a good idea, but that depends on the numbers. Use a TDS meter to check necessity. Under 20-25mg/l TDS is acceptable, up to 10 would be optimal. If it exceeds 25-30mg/l even after flushing a new membrane is advised.