Slow R.O. unit

Discussion in 'Hardware & DIY' started by pirate, 16 Apr 2009.

  1. pirate

    pirate Newly Registered

    Hi ,every-one,
    This is my first post on this site, so please excuse any bad form etc. My problem is this: I was always wondering why I couldn't grow decent plants in my tank-only plenty of algae. I recently started seriously investigating why this was happening and came to the conclusion it is due to my tap-water. When I tested it I was amazed to see the phosphate reading was off the scale. To try and get round this, I started using rain water mixed with tap water, this helped but means I have to rely on getting enough rain (not reliable in what is officially the driest place in the country). The only other alternative was an R.O. unit which i bought a few weeks ago. However, it now seems my tap pressure is not great enough to produce a decent amount of R.O. water but plenty of waste, in fact it takes about one day to produce 5 litres of usable water-not nearly enough as I have a 215 l. tank.
    Does anyone have any solution to this, perhaps some sort of pump to increase the pressure? Any help/suggestions gratefuly received.
  2. TDI-line

    TDI-line Member

    Yaxley, Peterborough
    Hello and welcome to UKAPS,

    i've used RO units before, but when it comes to planted tanks, you really don't need pure water. Infact you'll find the majority of us add phosphate and nitrate too.

    What are you tank stats, lighting, substrate and plant dosing regime, and livestock?
  3. nickmcmechan

    nickmcmechan Member

    Dalkeith, Scotland
    would agree that those phisphates will be used up in a heavily planted tank

    RO units work of high tap pressure - if you want to use it then you will need a pump as well
  4. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Chicago, USA
    Hi, sorry but this conclusion is incorrect. As mentioned in the preceding posts tap water actually works better for plants than RO. Unless your tap water is high in herbicides there is no reason why it cannot grow spectacular plants.

    OK, well, first of all the readings on your test kit are illusions. Phosphate readings are meaningless on these kits as they are unreliable. Secondly, and most ironically, if you did have high phosphate in your tap that would be a good thing as phosphate is a critical requirement for plants. Whatever source told you that you need to remove PO4 from your water is ill informed. The situation is actually the opposite. It is entirely possible that one of the reasons you had algae was that you did not have enough phosphate.

    Solution is as follows:
    1. Throw all test kits in a bonfire and use the money to buy other things, like Potassium Phosphate.
    2. Navigate to the Tutorial and the Algae Sections of the forum and carefully study the following articles in this order:
    Setting up a 'higher' tech planted tank
    Good algae article

    After reading feel free to ask questions. You'll find that what you have been led to believe about the causes of algae and the optimization of plant health have been totally false. In fact you don't need the RO unit at all so you can save yourself a lot of trouble by focusing on the real issues of plant growth.

  5. chris1004

    chris1004 Member

    Hi 'pirate' and welcome to this forum.

    Clives (ceg4048) advise is spot on as always and I can vouch that time spent reading those articles is time very well spent, they certainly helped me.

    With regard to your RO unit you can buy a pump to increase water pressure which will speed up the production of RO water or use a large barrel so that you can leave it on 24hours a day.

    Plants don't require Ro water though and its used primarily (freshwater) to produce soft acidic water conditions to keep some of the more delicate species of fish in.
  6. pirate

    pirate Newly Registered

    Thanks to all for your replies.
    I have read all the suggested articles and found them very interesting and informative. However, this does not answer my initial question. I realise I do not need to use R.O. water, I realise I need some Po4 for plant growth, that is why I intend to use 50/50 tap/R.O. water or R.O. water with the necessary addditives.
    Using the E.I. dosing method is not possible for me as I'm disabled and as previously stated, I have a 215l tank. That would mean changing more than 100l per week, walking with crutches carrying buckets of water isn't easy, and the most I can manage is 50l which I do every week.
    I do not rely on test kits but I have observed over the past 4 years I've had this tank, that if I use only tap water, the plants do not grow as well as they should, the fish look dull and dreary and I have had virtualy every type of algae known. When I use rain/tap water, the tank improves within weeks. Because of this I thought I would look closer at the cause - that is when I started testing the water.
    Am I alone in thinking test kits must be of some use, how else can one test for ammonia, Ph, Kh, Gh etc?
    Also, as previously stated, I cannot rely on enough rain to replenish my already dwindling stock, that's why I bought a R.O. unit, one that delivers very slowly!!
    For those interested, the following is my set-up/stats;
    25l tank
    plain sand
    1x Eheim Pro 2224, 1x Eheim Pro 2324 Thermo
    2 w/pg T8 lighting
    4x 2l D.I.Y. Co2, 1 bottle changed every 5 days (I know, not ideal, but as someone on this site said "Better some than none at all". I'm looking into going down the F.E. route)
    Po4 - 5
    Nitrite - <0.1
    Nitrate - 5
    Ph - 6.5
    Kh - 40
    Gh - 100
    Iron (c) - 0
    Iron (non c) - 0

    If anyone has any further ideas / suggestions I would be most grateful
    Thank you
  7. Ed Seeley

    Ed Seeley Member

    I think it might be the best bet for you if you sorted out some kind of water change system. This is a lot easier than it sounds and could save you loads of effort regardless of what amount you change!

    All you would need to do on your tank is to install a tee piece on the return pipes of one of your externals and connect a click on hosepipe connector to it to pump the water out!

    Even easier might be to buy a cheap little pump (a bargain pond pump might be ideal) and connect it to a piece of hosepipe. To pump water out you can just stick the pump in the tank and then put the end of the pipe in the sink or bath (or, even better, on the flowerbeds outside so you're not wasting water). Then to top the tank back up put the pump in your container of RO water and pump the new water back in! No more lugging any water around!

    As to solving your RO's slow flow - first of all they are really slow at the best of times! Water will only drip out and it takes mine overnight to refill my barrel of water. What I do is have my RO unit feeding into a 100l barrel with an automatic shut-off valve on it. Once the barrel is full it stops the RO unit working. If you had that system running you could just drop the pump into the barrel when refilling and just switch it off when the tank's full!

    The other things worth checking are the pressure of the mains water and also check that the prefilters aren't blocked (but if it's a new unit the latter shouldn't be a problem).
  8. Dolly Sprint 16v

    Dolly Sprint 16v Member


    I was concerned regarding water changes - so I post a thread and this was the reply:


    I have slightly altered there method no pump, I place a hose pipe into the tank - good suck on the pipe pardon the pun and I let gravity do the rest. As for filling I attached the pipe via a hozelock connection to the mixer tap - adjust the tap till I get the right temp then put the other end of the pipe into the tank and it fills its self.

    here is another section from a thread I added too.

    every body will confirm this 50% water change is recommended if you intend to use E.I. I have one hose pipe which empties and fills: one end has a strainer ... 240%3A1318 so the fish don’t go up the pipe and the other end has a no return valve ... 240%3A1318 and a mixer tap connection ... 240%3A1318. I initially draw of 50% of water (gravity feed) and it goes down the plug hole, as for filling I mix my water (hot & cold) to the desired temp prior to filling (aim for 70 degree C) pinch the pipe and then release the pipe once in the tank and fill to the desired level - whilst its filling i add my dechlorinator. Easy peeze all done in about 20 mins.



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