Best Reverse Osmosis system for drain to waste soil?

johndoe12345678

Well-Known Member
What's is the best RO unit for my top drip drain to waste soil grow, need a system that can do around 50-75gpd. There is a lot of RO systems to pick from, ones that give you neutral ph plus calcium and ones that remove all calcium and lowers the ph. Does anyone have any recommendations? I'm waiting on a water report but the water comes from a spring. If its anything like the water from my cities tap it has ph of 8.5 and a average ppm of 200. I've looked into a few different brands, I need help deciding which would be the best for my situation, Attached is a few I've been looking at.
 

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Headgrinder

Well-Known Member
If its for watering your garden, ive heard using reverse osmosis water and distilled water will cause minerals to leach out of the surrounding soil and tissue. This process is similar to what epsom salts do when ingested. When pure water can interact with electrolyte containing water through a membane or otherwise, the electrolytes will gravitate toward the pure water until a balanced condition where electrolytes are evenly distributed on both sides of the membrane occurs. If you are watering with alkaline water, you can add peat, or sulfur, and phosphorus additives. Everything might grow great with out doing anything exept using tap water too. Id also advise to get a second opinion too.
 

Renfro

Well-Known Member
If you plan to feed your plants or at least add some calmag to the water to replace the stripped minerals then you are on the right track. If you intend to water with straight RO then I would advise just using pH adjusted tap water.

TBH if it's spring water, then you may have a rather ideal calcium / magnesium content. Lets see what the water report says before we go down the RO rabbit hole. You may find that you would simply be replacing what you are stripping out. Once we see whats in the water we can add just what little if anything (cal mag) that it's lacking.

Do remember that the GPD rating on systems is based on a higher water pressure than you might have and therefore you may require a booster pump to get there. Lower pressure means more wastewater to create a given amount of clean water. An RO filter wastes a lot of water so you will draw like 4-5 times the water you actually use. This plus membrane costs means that small scale growers are best to avoid this unless they really need it. If you can justify it for drinking water perhaps thats a good excuse, just know that the first time you have to change filters you will see what I mean... it's a hassle.

Avoid filters that have a mineral/alkaline post filter, those actually add crap back into the water for flavor. If you want more hassle and super clean water you can opt for a DI post filter but I find that a good RO membrane will get my 180 PPM water down to 3 - 5 PPM.

I can't recommend a small filter as I haven't bought one in a long time but they are all basically the same thing, the filter cartridges are standard unless you get some really funky setup. The membrane quality will determine water quality, so any filter housing could be upgraded or downgraded with a membrane change. One way that you can go is buy a cheap system and when you have to change filters, replace them with really good ones. I like Axion membranes, they really do the job.

They take a while to make the filtered water so you will likely want a drum with a float valve setup to collect water.

I hope all that helps you.
 

johndoe12345678

Well-Known Member
If you plan to feed your plants or at least add some calmag to the water to replace the stripped minerals then you are on the right track. If you intend to water with straight RO then I would advise just using pH adjusted tap water.

TBH if it's spring water, then you may have a rather ideal calcium / magnesium content. Lets see what the water report says before we go down the RO rabbit hole. You may find that you would simply be replacing what you are stripping out. Once we see whats in the water we can add just what little if anything (cal mag) that it's lacking.

Do remember that the GPD rating on systems is based on a higher water pressure than you might have and therefore you may require a booster pump to get there. Lower pressure means more wastewater to create a given amount of clean water. An RO filter wastes a lot of water so you will draw like 4-5 times the water you actually use. This plus membrane costs means that small scale growers are best to avoid this unless they really need it. If you can justify it for drinking water perhaps thats a good excuse, just know that the first time you have to change filters you will see what I mean... it's a hassle.

Avoid filters that have a mineral/alkaline post filter, those actually add crap back into the water for flavor. If you want more hassle and super clean water you can opt for a DI post filter but I find that a good RO membrane will get my 180 PPM water down to 3 - 5 PPM.

I can't recommend a small filter as I haven't bought one in a long time but they are all basically the same thing, the filter cartridges are standard unless you get some really funky setup. The membrane quality will determine water quality, so any filter housing could be upgraded or downgraded with a membrane change. One way that you can go is buy a cheap system and when you have to change filters, replace them with really good ones. I like Axion membranes, they really do the job.

They take a while to make the filtered water so you will likely want a drum with a float valve setup to collect water.

I hope all that helps you.
I found a older water report, can i get away with just using pH adjusted tap water?
 

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Renfro

Well-Known Member
I found a older water report, can i get away with just using pH adjusted tap water?
That test is not comprehensive, it only shows lead, copper and bacteria. Just to show it's safe to drink. A full report would show everything as mg/L (PPM). So you would see numbers for calcium and magnesium.

You can get those water test kits that you mail off and get a full report. Honestly if your plants are happy then why worry? If you need to get complicated then do so but the idea of a soil grow is simplicity.

What are your plans for feeding? If you are just watering organic soil I would stick with the tap water. If you are feeding with bottles, you could proceed without any calmag and just base nutes. If they show signs off needing magnesium you can add some epsom salt. Chances are the calcium is covered with the water PPM, possibly the magnesium as well.
 

johndoe12345678

Well-Known Member
That test is not comprehensive, it only shows lead, copper and bacteria. Just to show it's safe to drink. A full report would show everything as mg/L (PPM). So you would see numbers for calcium and magnesium.

You can get those water test kits that you mail off and get a full report. Honestly if your plants are happy then why worry? If you need to get complicated then do so but the idea of a soil grow is simplicity.

What are your plans for feeding? If you are just watering organic soil I would stick with the tap water. If you are feeding with bottles, you could proceed without any calmag and just base nutes. If they show signs off needing magnesium you can add some epsom salt. Chances are the calcium is covered with the water PPM, possibly the magnesium as well.
I figure that wasn't a very detailed report i couldn't understand why there wasn't any ppm readings,
So many options been having a hard time deciding, i was gonna do all rooms with soil top drip to waste with manifolds, but then you mentioned how much easier flood to drain was so it got me wanting to do that, I ended up with 30 gallons of fox farms nutes, I did some research and heard using organic nutes in hydro systems can cause problems, so now im leaning back towards soil, Im debating on buying another pallet of soil of just getting some flood tables and a RO unit. I just want everything to be as automated and simple as possible.
 

johndoe12345678

Well-Known Member
That test is not comprehensive, it only shows lead, copper and bacteria. Just to show it's safe to drink. A full report would show everything as mg/L (PPM). So you would see numbers for calcium and magnesium.

You can get those water test kits that you mail off and get a full report. Honestly if your plants are happy then why worry? If you need to get complicated then do so but the idea of a soil grow is simplicity.

What are your plans for feeding? If you are just watering organic soil I would stick with the tap water. If you are feeding with bottles, you could proceed without any calmag and just base nutes. If they show signs off needing magnesium you can add some epsom salt. Chances are the calcium is covered with the water PPM, possibly the magnesium as well.
Talked to water guy he said water pH 7.9, tds ppm270. He said water is slightly high in chlorine. Will i be fine using pH adjusted tap water and letting it sit out for 24 hours to let chlorine evaporate?
 
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Headgrinder

Well-Known Member
The healthier your soil the better it is a neutralizing any chlorine. But if chlorine does do anything it is small and unnoticeable, and possibly out weighed by the benefit of having disinfected water. However the amount of chlorine can vary from different treatment plants. Yes chlorine will evaporate from your water in 3 days. One other thing to consider is the studies linking treated water and sex mutations in fish due to chemicals still present in treated water. I think they were thinking the metabolized birth control pill may linger in water after treatment and I'm sure there were other chemicals too. I use my city water. But it's a pretty small town so there is no chlorine and as far as I know no treatment facilities. The only hermies I've ever had, I'm 99% sure, were my fault. I wouldn't worry about that unless I lived in NY or Detroit someplace like that. Sorry people from those cities, I am an ignorant bumkin.
 

Renfro

Well-Known Member
Talked to water guy he said water pH 7.9, tds ppm270. He said water is slightly high in chlorine. Will i be fine using pH adjusted tap water and letting it sit out for 24 hours to let chlorine evaporate?
The chlorine wouldn't be a problem as you can let it evaporate so long as it's chloramine. The real numbers you need is the PPM of Calcium, Magnesium and Iron.
 

johndoe12345678

Well-Known Member
What are the maximum ppms of magnesium and calcium before I would start having issues? I've read about people having problems with hard water in there garden. My water leaves stains in sink and toilet, I just wanna make sure it will work with no problems. Hate trying to solve problems in the middle of run instead of being prepared.
 
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Renfro

Well-Known Member
I have grown with worse h2o. The bicarbonate may be of more concern than anything else. Something doesn't line up in the numbers though, not sure exactly why, perhaps overlap in some of the numbers? Of course I am not seeing the whole report, I don't know what their total PPM was, only that you sated in the OP the 200 number. The bicarbonate PPM of 161 is most of that right there, and is probably the most concerning number.

Was this test done on water from your tap? Not the water plant. A lot can happen to the water on it's way to you.

I would be interested in seeing the actual report, just block out the personal information, a lot more can be learned from looking at the whole puzzle and not just a few pieces. Either way these are my thoughts regarding your water.

The calcium and magnesium numbers are low enough that you would want to add some form of calcium and magnesium. Your base nutes may have enough ca and mg to get you there during veg but if you veg long and definitely in flower you may wanna add a 50 - 66% strength dose of calmag to the mix. The plants will tell you where they want to be just make sure you take into account other factors like pH, water temperature, abundance of other elements. Generally somewhere around 250 - 300 PPM total of calcium / magnesium is a good place to start, I tend to be around 150 PPM calcium and 60 - 70 PPM mag but a little more like 90 - 100 magnesium if using coco. If you are using coco and see a mag def and you already have ample calcium in the mix you should add epsom salt instead of calmag to boost the magnesium without adding more calcium. The sulfur helps with terpene production as well so I am not concerned there. FWIW there is a link in my signature that may shed some light on your feed numbers and the whole elemental PPM - mg/L thing works if you don't know already.

I am sure that someone more versed in the science of water could give you more but the bicarbonate number may be the thing that would most warrant filtering.

This is a little tid bit that explains the bicarbonate situation

Source of Bicarbonate

The Bicarbonate (HCO3) ion is the principal alkaline constituent in almost all water supplies. Alkalinity in drinking water supplies seldom exceeds 300 mg/i. Bicarbonate alkalinity is introduced into the water by CO2 dissolving carbonate-containing minerals. Alkalinity control is important in boiler feed water, cooling tower water, and in the beverage industry. Alkalinity neutralizes the acidity in fruit flavors; and in the textile industry, it interferes with acid dying. Alkalinity is known as a "buffer".

Treatment of Bicarbonate

In the pH range of 5.0 to 8.0 there is a balance between excess CO2 and bicarbonate ions. Removing the free CO2 through aeration can reduce the bicarbonate alkalinity. Feeding acid to lower the pH can also reduce the alkalinity. At pH 5.0 there is only CO2 and 0 alkalinity. A strong base anion exchanger will also remove alkalinity.


Of course aeration will not only bring down Co2 but will also transform the bicarbonate to carbonate, carbonate and calcium partially drop out (precipitate) thus reducing alkalinity. Still have garbage overhead.

In the end, can you grow with this water, yes most likely without much issue other than the bicarbonate / alkalinity where the simplest solution is adding a pH down buffer such as phosphoric acid, of course further increasing "overhead PPM" and likely have to deal with some drift. It should be noted that the water isn't always a constant, my water comes from a reservoir and it has seasonal fluctuations and sometimes our magnesium spikes.

I use an RO filter personally just because it gives me a clean slate that I can depend on. This makes the water a constant and not a variable.

In your case it would really come down to fighting the pH drift. If you find thats not a problem then running sans filter will be the way to go IMO.

As to the filters in the OP, the one that "adds calcium" likely has a alkaline post filter cartridge thats adding minerals back into the water for flavor and to raise the pH, you do not want that type of filter. If you end up with one you can simply bypass that post filter and not use it.

Man this is a really poorly written post and I apologize for that, it's late and I am very high and even more tired.
 

Nizza

Well-Known Member
I installed my RO unit under my sink and it feeds a water tap that is mounted to my sink, this is where I get my drinking water
I use the alkaline calcite post filter to keep it safe for drinking, and installed a Tee before that post filter. I just pull the 1/4" line out from under my sink and open a ball valve on that line to fill my res up so I don't get the calcite in there
 

SheeshM

Well-Known Member
I have the micro75 shown in the second photo. I bought in when I switched mediums from soil to coco/perlite and it worked well for my small grow. I use about 20 gallons a week for 4 plants so it wasn't too tough to manage. The water pressure decreased a lot about half way through my 2nd grow and I had to change the pre-filter to fix it. I ended up changing the membrane too but I've read that changing the pre-filter sooner can extend the membrane life. As someone mentioned, the 75 GPD is dependent on the water pressure in your space.
 

Nizza

Well-Known Member
I have the micro75 shown in the second photo. I bought in when I switched mediums from soil to coco/perlite and it worked well for my small grow. I use about 20 gallons a week for 4 plants so it wasn't too tough to manage. The water pressure decreased a lot about half way through my 2nd grow and I had to change the pre-filter to fix it. I ended up changing the membrane too but I've read that changing the pre-filter sooner can extend the membrane life. As someone mentioned, the 75 GPD is dependent on the water pressure in your space.
get the booster pump and you won't look back
 

Renfro

Well-Known Member
I have the micro75 shown in the second photo. I bought in when I switched mediums from soil to coco/perlite and it worked well for my small grow. I use about 20 gallons a week for 4 plants so it wasn't too tough to manage. The water pressure decreased a lot about half way through my 2nd grow and I had to change the pre-filter to fix it. I ended up changing the membrane too but I've read that changing the pre-filter sooner can extend the membrane life. As someone mentioned, the 75 GPD is dependent on the water pressure in your space.
Yes slower production rates indicate time to change the pre filters, and yes doing that in a timely manner really helps preserve membrane life.

I found this a handy little item, to detect slower production rates.

 
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