Questions about osmosis filtering

[KinkyCerebro]

Hello! I'm starting a Hydroponic set up but the water in my city is very bad, i get around 550 ppm from the get go. I was thinking of getting a reverse osmosis filter but was unsure on what to look for, what to buy or what not to buy. I'm from Argentina so I might be limited as to what I can get, so keep expectations to a minimum. I've seen some that are not as expensive and say that can filter 400 liters per day, I will need 150 liters a week so that means that I only have to use the filter for 9/10 hours once a week? I'm not sure if i get how this works and I need to do numbers, so any information helps. Thank you in advance!

 

[Creeperpark]

If you don't purify your water you will most certainly fail. You will have to have RO water and you will need to spend enough money to get a good one. You can get 3 or 6-stage RO systems. I would start with anything I could get my hands on. All that matters is low ppm and almost pure water.

 

[Nannymouse]

I don't know much about r/o units, even though we've had them in most every place that we've lived for the past 20 years or so.

Ours have always been 'under the sink' and have a pressurized tank, which is not very big, but keeps up with our drinking water and cooking needs. If i were to be needing a large amount just once a week, i would have to run a gallon out every day, and save that in water jugs until needed. The only problem that we've had is that ours 'back washes' and there is a setting for that function. We tested the water and it was super high pH, far higher than the tap water, which is already over neutral. We had to increase the times that the filters washed themselves out, then everything was okay. It is something to check, if things are not going right, or before things go wrong, ha.

 

[KinkyCerebro]

If you don't purify your water you will most certainly fail. You will have to have RO water and you will need to spend enough money to get a good one. You can get 3 or 6-stage RO systems. I would start with anything I could get my hands on. All that matters is low ppm and almost pure water.

well i bought a 5 stage one with backwash and 5 microns in the last stage, I know people who do Hydroponics with tap water and it turns out fine, i just don't trust my hometown's tap water.

 

[Creeperpark]

Reverse osmosis is important because plants use osmosis the same way in their root systems. Everything is filtered before entering the plant. When a liquid solute comes in contact with the roots the plants use osmosis to screen and purify at the entry point. IF one uses tap water the impurities can block the entry points or receptor sites. When using RO water the water is already perked so to speak and entry into the plant's system is easy for the incoming solute..

 

[Creeperpark]

The thing to remember when using RO water is that the water is much more potent. It only takes a little fertilizer to do what a lot of fertilizer does with tap water. RO or Rainwater, the nutrient charges are much stronger and last longer. Since the water is so potent one may need to buffer it with a little cal-mag. If you are going to invest in indoor grow, "RO is the way to GO". Good luck Friend.

 

[KinkyCerebro]

Thanks for the in-depth response!! So the way to measure if i need to add cal-mag is by the ppm count?

 

[Switcher56]

Reverse osmosis is important because plants use osmosis the same way in their root systems. Everything is filtered before entering the plant. When a liquid solute comes in contact with the roots the plants use osmosis to screen and purify at the entry point. IF one uses tap water the impurities can block the entry points or receptor sites. When using RO water the water is already perked so to speak and entry into the plant's system is easy for the incoming solute..

KY Jelly LOL

 

[Creeperpark]

Thanks for the in-depth response!! So the way to measure if i need to add cal-mag is by the ppm count?

Yes, that's the best way to watch cal-mag or any incoming nutrient content. Take the pure RO or Rainwater and get a ppm reading first. After the first reading add a couple of measured ml of cal-mag to the RO stir and get a second ppm reading. Knowing the ppm of the addition of 2 ml will allow you to set the total amount per gallon. Heres an example.

I take my pure water and get a reading first. (7) ppm.
Then, I add my 2 ml of cal mag to the water,,wait, stir, I get 2nd reading (46ppm)
Now if I want water that is (126) ppm to buffer a lot of fertilizer, I now know how much extra cal-mag to add.
Im doing a low watt grow now so my cal-mag ppm is only (70)ppm before adding fertilizers. .

 

[Douglas.Curtis]

KNF water soluble calcium works wonders, and no extra mag or nitrogen. You'll love how easy it is to make. Magnesium sulfate works great to supply magnesium with a bit of sulfur when needed.

I use straight r/o, unpH'd, and supply the calcium mainly through foliar sprays. Never been a fan of calmag. lol

 

[Creeperpark]

When using liquid fertilizers with RO water the water has to be buffered with precision and that's cal-mag's job.

 

[Creeperpark]

KNF water soluble calcium works wonders, and no extra mag or nitrogen. You'll love how easy it is to make. Magnesium sulfate works great to supply magnesium with a bit of sulfur when needed.

I use straight r/o, unpH'd, and supply the calcium mainly through foliar sprays. Never been a fan of calmag. lol

Your organic right?

 

[Douglas.Curtis]

Yes, I dumped all my hydro stuff last year and have switched to rabbit and KNF.

Almost 20 years with r/o and and hydro... never used Calmag or pH'd water addbacks. Because most calmag has extra nitrogen I never needed and pH'd/buffered addbacks mess with the very important pH swing.

 

[Creeperpark]

Yes, I dumped all my hydro stuff last year and have switched to rabbit and KNF.

Almost 20 years with r/o and and hydro... never used Calmag or pH'd water addbacks. Because most calmag has extra nitrogen I never needed and pH'd/buffered addbacks mess with the very important pH swing.

I use calcium carbonate Gen. Organics without nitrogen, I never use pH up or down.

 

[moose eater]

My well water is a total hardness of ~380 or ~390 the last time we checked. I've been told in the past that the ideal hardness for cannabis cultivation is about 150.

I've used R/O systems in the past, the last one being a 3-stage unit.

I now have a new R/O D/I system (waiting to be hooked up for the last several years), though I've been using the hard tap water from the well.

Total PPM can be adjusted by adding lesser nutrients, but still enough, and dropping the ph a bit (I stay around 6.2 to 6.4 these days).

When I used the old 3-phase RO system, I sometimes mixed it 50:50 or there-abouts, with straight well water, and other times not. If using straight RO D/I H2O you may want to mineralize your water with calcium, magnesium, etc. I rarely did. Back then we loaded water and mixed in a 33-gallon trash can as described below.

The plan with the newer RO DI system is to mix the well water and treated water 50:50 in the classic 33-gallon ruff-neck/rough-neck Rubbermaid trash containers we often use for the gardens here. They'll hold up pretty well, though I doubt they lack toxins in the manufacturing of them. They're not exactly made for potable water.

Skip, our former techie/admin here at ICMag used an i-Spring unit he referenced when he and I had this discussion a couple years ago or so.

Another member turned me on to an online store/site called 'Air, Water & Ice', which is where I ended up buying my current (yet to be installed) RO DI system at, which is a 5-stage with De-Ionization.

Caution!! There are ways in which to plumb your RO DI or RO system so that you minimize the waste water effluent, which can be as much as twice the volume of your RO DI output; as in, 1 gallon treated water can produce up to 2 gallons or more down your drain as waste water, carrying salt(s), etc., which if you're on a steel welded septic tank, you may want to come up with plan B.

Also, when you hook up your system, there are several different types of shut-off valves for your reservoir or trash can. Some will divert water back to your drain, and continue purifying water while you're not looking, sending it AND your waste water down the proverbial tubes while your system continues 'cleansing' water for no good reason at all, and costing you money.

Another shut-off valve (if made properly) will shut off the flow of water.. period. No redirecting back to your waste water drain, etc. USE THAT ONE, if you can get one made of good quality.

Nothing screams "SON OF A BITCH!!" in the middle of the night like waking to find your RO DI unit has flooded your basement, shop, bedroom, etc. Good quality equipment prevents excess aspirin consumption. Personal experience.

 

[moose eater]

Also, there's a fair bit of junk in the market for such devices. Go with a manufacturer and vendor who has reasonable prices and a STELLAR rep. A few bucks may save you a bunch more.

For the garden, I use a faucet adapter on the basement sink, hook the unit to the wall using a 2"x4" or 2"x6" backer across the studs, and use bits of fine chain (small stuff, really) to hang tubing from the ceiling with screws into ceiling joists. A waste water drain is a red tube that runs to a utility sink, and is kept in place with a small pipe retainer that screws into the polymer utility sink.

No permanent plumbing necessary. make your RO DI unit for the garden as mobile as you like, and when you need to replace it, it's not so big of a pain in the ass.

For the drinking water RO, we have an under-sink Kinnetico, which is sort of an expensive 'club-type' affair. They like their products a LOT, and you can only get them through their dealers. Don't ask what we paid for the newest one. It was ridiculous!! Portable salt water aquarium RO DO units will often come with the sink adapters and such, too. Air Water & Ice, if they're still in business, can send you all that stuff, and maybe cut you a decent deal, as well as technical support, when/if you buy from them.

Don't buy from ANYONE who doesn't know their product, the science, or misrepresents their stuff's capacity/capability.

 

[troutman]

I now filter my water thru activated carbon and find my plants are happier.

I'm dabbling with Deionization Resins (DI) as well.

Deionization Resin (DI) is the last stage of the RO/DI system and is necessary to reduce Total Dissolved Solids (TDS) to zero.

I'll take pics of my DIY water cleaning system soon. No plumbing or power required.