how to use RO water

[Kendramc]

i have really hard water (no specific numbers currently, but at least 240ppm KH/180ppm GH with a pH of 7.5). at the moment i have bristlenose plecos and swordtails in this water, but would like to try something different and am looking into options for less hard of water. my husband wants to get an under sink type RO system and i was wondering if i could use RO water/how i use it.

i think his plan it to have the RO system use water after it goes through the softener system. i do know enough to know that i don't want to use softened water in my tank, but i don't know enough to know about RO water.

and i know that swordtails like hard water, don't worry about that part right now.

any advice is appreciated.

 

[Colin_T]

If you are unsure of the actual GH and KH numbers, this information can usually be obtained from your water supply company's website (Water Analysis Report) or by telephoning them. If they can't help you, take a glass full of tap water to the local pet shop and get them to test it for you. Write the results down (in numbers) when they do the tests. And ask them what the results are in (eg: ppm, dGH, or something else).

Depending on what the GH of your water is, will determine what fish you should keep.

Angelfish, discus, most tetras, most barbs, Bettas, gouramis, rasbora, Corydoras and small species of suckermouth catfish all occur in soft water (GH below 150ppm) and a pH below 7.0.

Livebearers (guppies, platies, swordtails, mollies), rainbowfish and goldfish occur in medium hard water with a GH around 200ppm (mollies need a GH of at least 250ppm) and a pH above 7.0.

If you have very hard water (GH above 300ppm) then look at African Rift Lake cichlids, or use distilled or reverse osmosis water to reduce the GH and keep fishes from softer water.

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A general hardness (GH) of 180ppm is just above soft water and at the bottom end of medium hardness water. It is fine for tetras, barbs, angelfish, gouramis, Bettas, most catfish, etc. If the GH is 180ppm, then you have a wide range of fish to choose from.

 

[seangee]

If you mix it 50/50 with tap water you will halve the hardness, so 120ppm KH / 90ppm GH (using your numbers). You also won't need to use dechlorinator. It doesn't matter if it goes before or after the softener because the RO will take out anything the softener adds.
But if you don't want to mix it with your softened tap water you can either

• mix it with water from a garden tap (or one that does not go through the softener
• Use pure RO water and add back minerals to get to the hardness you need - I use a one shot mix like Salty Shrimp GH+/KH+ for the tank that needs it

If you keep super soft water fish you could just use straight RO.
pH isn't really possible to predict (but it also isn't really important)

 

[Kendramc]

A general hardness (GH) of 180ppm is just above soft water

That is where the test strips i have max out, so it is higher than that.

If you are unsure of the actual GH and KH numbers, this information can usually be obtained from your water supply company's website

I've checked, their report doesn't have hardness. If we do get an RO system I will get a drop test for it to get exact numbers, but until then it doesn't really matter that much.

mix it with water from a garden

Perfect, I was hoping it was that easy

 

[StevenF]

i think his plan it to have the RO system use water after it goes through the softener system.

RO water can be mixed with unsoftened water to achieve the desired hardness you want. You do not want to mix it with softened water because all of the calcium and magnesium has been removed and replaced with sodium bicarbonate water pressure in animal cells is chemically regulated by the body. This is often referred to as oxmotic balance. Calcium, magnesium sodium and potassium all play a role in osmotic balance. If the Ca, Mg, Na, and K element levels are too fare out of normal ranges for the fish in your tank the health of the fish can be severely compromised.

You need to find a faucet in your home or yard that is not connected to the softened water from your water softener. Typically outdoor facets are not connected tot he water softener.

Water from your softener would have a very low GH but a very high KH. While natural water typically either equal values of GH and KH. Often with slightly more GH then KH. Aquarium test strips can be used to quickly test the water from each focet on your property to identify the faces with unsoftened water.

Also note that under sink RO systems are typically limited to about 20 gallons of RO water a day. and typically only have a RO storage tank that is limited to storing between 1 to 3 gallons of RO Water. The size of the tank is ideal for drinking and cooking. But not enough for larger aquariums. You an drain the RO tank once a day and store this water is container for your aquarium. Or you cana get a larger RO water storage tank to replace the small on that fits under your sink.

Another option is to get a under sink RO system and then a separate RO system that can produce a 50 to 100 gallons of RO water per day. They can be connect when needed to a facet and quickly disconnected when you have the water you need. Such as this system.

 

[StevenF]

https://www.amazon.com/Aquatic-Life...pY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU&th=1

 

[seangee]

Also note that under sink RO systems are typically limited to about 20 gallons of RO water a day. and typically only have a RO storage tank that is limited to storing between 1 to 3 gallons of RO Water. The size of the tank is ideal for drinking and cooking. But not enough for larger aquariums. You an drain the RO tank once a day and store this water is container for your aquarium. Or you cana get a larger RO water storage tank to replace the small on that fits under your sink.

This is important. I initially bought a 50GPD system. I very quickly upgraded the membrane to 100GPD. This took almost an hour to produce 10 litres of water (sorry I don't actually know what a gallon is ). Since I typically change around 220 litres a week this meant a couple of days to refill containers for the next water change. Last year I treated myself to a 400GPD "direct flow system". This actually takes up less space under the sink as it has no storage tank, but it gets me 10 litres of RO water in around 15 minutes. It also wastes less water. I still refill the containers immediately after my WC but can now comfortably do all 4 tanks in a day.

This is the one I have https://www.osmiowater.co.uk/catalo...al-surgery-reverse-osmosis-system/category/4/ FWIW the reason for the dental system is the final stage is DI resin. The home system comes with a re-mineraliser. I don't trust that as they don't tell you what goes in it and the mineral content changes as the filter depletes, I want my water to be the same all the time. Don't actually need DI so removed that stage once it was depleted.

P.S. I can guarantee that after the first time you replace your pre-filters you will never drink tap water again . Added bonus is zero limescale in the kettle, coffee machine, clothes iron etc.

 

[Back in the fold]

I use a reverse osmosis unit for my aquarium water and everyone here said it all. You have all the information you now need.