# Hard Water or RO, which is better?



## Andy D (25 Sep 2013)

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?


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## Andy D (25 Sep 2013)

Anyone use hard water in a high-tec set-up?


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## sa80mark (25 Sep 2013)

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


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## Andy D (25 Sep 2013)

I know those white marks only too well! 

Would you say you face any difficulties in any particular aspect? I read somewhere that you have to run CO2 at higher levels in hard water set-ups but not sure if this is the case?


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## Ian Holdich (25 Sep 2013)

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...


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## sa80mark (25 Sep 2013)

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


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## Andy D (25 Sep 2013)

Fortunately at least I am not on a water meter.


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## Andy D (25 Sep 2013)

sa80mark said:


> 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.


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## Nathaniel Whiteside (7 Oct 2013)

Ian Holdich said:


> 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


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## DrRob (7 Oct 2013)

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.


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## Ian Holdich (7 Oct 2013)

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.


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## Nathaniel Whiteside (7 Oct 2013)

DrRob said:


> 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.




Ian Holdich said:


> 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.


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## Andy D (7 Oct 2013)

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.


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## Ian Holdich (7 Oct 2013)

Andy D said:


> 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.


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## ian_m (7 Oct 2013)

Nathaniel Whiteside said:


> 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.


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## Andy D (7 Oct 2013)

So lets just say the typical mains pressure is 3 bar. The RO membrane will reduce this to say 1 due to the resistence. So the pump forces the water through at a higher rate to get nearer to the mains 3 bar pressure.


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## ian_m (7 Oct 2013)

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.


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## DrRob (7 Oct 2013)

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.


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## ian_m (7 Oct 2013)

DrRob said:


> 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%.


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## Nathaniel Whiteside (7 Oct 2013)

ian_m said:


> 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


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## ian_m (7 Oct 2013)

Nathaniel Whiteside said:


> Where would we find a flow reducer ian?


Flow reducer usually comes matched with your RO unit. I say usually, as just found
Reverse Osmosis Consumables - Flow Restrictors - Osmotics Water Filtration

Also if fitting an RO unit, get an auto shutoff valve. http://www.osmotics.co.uk/products/Auto-Shutoff-Kit-with-Float-Valve.html
See here Installing an Auto Shut Off Valve - Instructions  - Bulk Reef Supply how they work.

This enables you to have the RO unit permanently connected to mains water (except via maintenance isolating valves), you just turn on your RO output valve, in the shed in my mates case say 20m away, and it opens the water in and RO water flows.

Also auto flush units are useful as some cheap RO units require you to disconnect the outlet pipe to flush the unit. Basically you remove the flow reducer to allow full pressure water to flow through for a minute or two every so many hours of operation.

Look auto flush units as well.
Auto Flush Solenoid Valve - Osmotics Water Filtration



Nathaniel Whiteside said:


> like your auto heating water butt


Still in use once a week. Still "twitchy" though about having mains pressurised hose pipe in the lounge near TV, sat box etc. But really save time for a 90litre water change.


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## ian_m (8 Oct 2013)

Oh and if you fit an RO unit you have a legal duty (ie people have been fined for not doing so) to inform the water board. See here. New Page 2. I think even a WRAS certified plumber has to as well.

I was granted it for my water softener, no problem provided a double check valve was fitted to the incoming mains supply. 15mm Double Check Valve | Screwfix.com

The court case were of incorrectly fitted RO units (and pump ?) pushing contaminated water back into the mains supply.

You will/may have issues selling your house if you haven't got the relevant paperwork....


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## foxfish (8 Oct 2013)

Wow that is interesting!! I am not sure if that applies where I live though - hope not as I must of fitted well over 20 & never registered any of them!


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## ian_m (8 Oct 2013)

foxfish said:


> I am not sure if that applies where I live though


Yes it does http://www.water.gg/sites/default/files/Water Byelaws.pdf

Plumbing | Guernsey Water

Looks like if an "approved contractor" (pg 6) fits a "water treatment apparatus" (pg 17) then automatic approval is granted or else approval has to be sought.

However in practice ??? I suppose as long as a double check valve is fitted to the incoming supply to protect the incoming supply if there is a pressure issue nobody will ever know.


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## foxfish (8 Oct 2013)

LOL OH well I hope I am an approved contractor!


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