• You are viewing the forum as a Guest, please login (you can use your Facebook, Twitter, Google or Microsoft account to login) or register using this link: Log in or Sign Up

Hard Water or RO, which is better?

Andy D

Member
Joined
27 Apr 2013
Messages
1,461
Hi All,

First up some tank details (if it matters):
Tank is a 30litre nano (Fluval Ebi) that is currently planted with Eleocharis Acicularis in a cat litter substrate. Hard scape is Lava Rock.
I have set up a FECO2 system running at about 2bps and drop checker is darkish green. I dose TNC Complete daily. (I am considering taking out the Eleocharis Acicularis and replacing it with Eleocharis Sp Mini (Tropica 1-2-Grow).

I have read articles that George has written stating that plants can be grown perfectly well in hard water but as i have an RO unit would I do better using RO? (RO can be remineralised, mixed with tap or left neat for now as I have no fauna in the tank but do plan on getting shrimp).

What do you guys think is the best route to go down?
 
Mines a hard water high tech tank well I believe its classed as hard water 19 - 20 dh around 450ppm the only problem ive had is the white deposit around the tank
 
I've used both, I have seen much different in the way of plant growth or health. I do notice that in to water, plants pearl quicker. I'll be reverting back to hard water in my next scape as the water meter really doesn't like ro water...
 
Ive been reading the same sort of thing but I havnt noticed that as a potential issues apart from a small algae outbreak on my last tank ive had good plant growth etc my co2 level at the minute is approx 5 bps but I have no livestock so am pumping it in my last tank ran very stable 2bps in 30l and was fine for livestock, im not sure if ive had no issues due to me doing large often water changes 80% everyday week 1, 80% every 2 days week 2 , then 80 % twice a week, this just works for me so its what I will stick to
 
Ive been reading the same sort of thing but I havnt noticed that as a potential issues apart from a small algae outbreak on my last tank ive had good plant growth etc my co2 level at the minute is approx 5 bps but I have no livestock so am pumping it in my last tank ran very stable 2bps in 30l and was fine for livestock, im not sure if ive had no issues due to me doing large often water changes 80% everyday week 1, 80% every 2 days week 2 , then 80 % twice a week, this just works for me so its what I will stick to

Thanks for the feedback. :)
 
I've used both, I have seen much different in the way of plant growth or health. I do notice that in to water, plants pearl quicker. I'll be reverting back to hard water in my next scape as the water meter really doesn't like ro water...

Hey Ian,

I can recall you telling a member to consider an RO booster pump.
My mains runs into the RO at between 3 - 4 bar, do you think I'd get any benefit whatsoever in terms of waste water reduction in purchasing one?
I'd think not, but I don't know much about pressures and the like.

Cheers,
N
 
Depends if anyone is using the shower while you're pumping RO.

Also will depend hugely on the local pipework. 1/8 inch is a real pain for pressure drop offs.

Yeah, I've got a pressure gauge on my RO, and I think it sits at about 3 3/4 to 4 bar. Which i think is good by the standard.


These are the pumps I was talking about

D&D RO Booster Pump | Swell UK

There are a couple of members who use them, and it can save a lot of water and time, if your on a meter. It'll still up the bar further.

Yeah, I thought you meant them mate.
So what pressure do you think they'll up it to?
I do get quite a bit of waste with it, maybe a 1:3 ratio pure : waste.

**** EDIT : Just seen it pushes 9 bar! That should. Be excellent and reduce my waste ratio to about 1:1.
 
Apologies if I have missed something but how does this increase presure? Surely it cannot increase on the speed the water comes out of the tap so I do not see how it increses the pressure going into the RO unit.
The ro unit lowers the pressure as it hits the unit due to the membrane, the pump just ups the pressure, before it hits the membrane. It can't up the pressure coming out of the tap.
 
Just seen it pushes 9 bar! That should. Be excellent and reduce my waste ratio to about 1:1
Note sure that is true, please correct me. I understand the pump just enables the RO membrane to operate at its optimal capacity all the time regardless of incoming pressure, temperature and "back pressure". So if membrane is 4:1 you will be getting 4:1 regardless of water temp.

Low pressure, low temperature and high back pressure (of output) all seriously reduce efficiency to say 5:1 to 10:1 to even 20:1 for extreme conditions.

Commercial RO units (expensive) get better efficiency as use waste water to pressurise the incoming water, to maintain higher pressure all the time.
 
The RO pumps boosts the pressure to 9bar odd, so you get a higher flow rate through the membrane, as flow is proportional to incoming pressure.

You need a "flow reducer" in waste water outlet which basically maintains the pressure in the unit. If you don't have one, or have incorrect size for the unit (as you have fitted a boost pump !!), the incoming water passes straight through the unit to the drain and ends up with far worse water wastage.
 
There's also the issue with the narrow pipes. Your 15mm copper has a fair amount of water in it at 3 bar. It doesn't take much to get the pressure up to 9 bar when you're measuring in 1/8 inch RO pipe.
 
Your 15mm copper has a fair amount of water in it at 3 bar
15mm pipe at 1bar or at 10bar or at 100bar still has same amount of water in it as water is incompressible.

1/4" pipe is fine for RO units as flow is quite low, which is why they are used in most smaller RO systems.

When my mate kept marines years ago he ran a 1/4" pipe long the 1/2 the length of his house, from kitchen to outside shed, where he kept the RO unit (and storage tanks) and pressure drop and/or lack of flow was not an issue at the flow rates needed for an RO unit.

Just found this, wonderful thing this web thing. Pressure Drop Online-Calculator

So for a 50gal per day RO unit (US gals = 190litres/day = 0.008litres/hour) allowing 4:1 waste gives 0.032litres/hour. Plugging in 6.35mm (1/4") for pipe and say a massive 20 meters gives a pressure drop of 33mbar that's 0.033bar on say 3bar is a pressure drop of about 1%.
 
The RO pumps boosts the pressure to 9bar odd, so you get a higher flow rate through the membrane, as flow is proportional to incoming pressure.

You need a "flow reducer" in waste water outlet which basically maintains the pressure in the unit. If you don't have one, or have incorrect size for the unit (as you have fitted a boost pump !!), the incoming water passes straight through the unit to the drain and ends up with far worse water wastage.


Where would we find a flow reducer ian? thanks for all the information thus far, your knowledge regarding water and electrics is great :) like your auto heating water butt :thumbup:
 
Back
Top