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Water changes on large tank?

Sacha

Sacha

Member
Joined
3 Jan 2014
Messages
992
Location
London
Hi guys,

I have had my 125 litre tank for a few years now, and I do 50% weekly water changes with RO.
We're having my room refurbished in May and I would like to get a bigger tank for when that happens. I'm looking at the Juwel Rio 300 and the Rio 400. The 300 is 350 litres, which would mean 175L water changes every week. The 400 is 450 litres, so 225L water changes a week.

Is this even possible using RO? How the hell am I supposed to store 200 litres of water in my room?
 
Does it need to be ro water you use ?Would a Hma filter not make it easier for you,I think it comes with 10meter of piping to run the water straight into your tank when topping up again .Plus no wastage of water like there is with ro.
 
Well then if you dont have a choice.....good luck. Sure it can be done, but is it worth it. Also unless you are breeding I dont see the point.
 
I keep Cardinal tetras. My tap water is TDS 350- 400, KH is above 10, GH is about 20.
 
Oh, phosphates are over 10 ppm and nitrates are about 40 ppm
 
One option is don't store it at all. Can you design your tank so it will work at half water level? That way, simply remove half the water, then allow it to slowly get refilled by RO output directly. The heater should compensate for the slow addition of water even if it is cooler. Depending on location of course you might need a long bit of tube. You can kinda manually remineralise by adding whatever you need as you go along. Some kind of level detection shut off would be advised to prevent overflowing.

Alternatively there's the possibility of split water changes, perhaps 25% twice a week instead of one 50%.

I would suggest getting a faster RO unit than I did. I got about 60L (my water change mix container) in about 8-10 hours today from a pumped 50gpd unit.

Otherwise if you need to store and move it, you will just have to find a way to store a lot of containers. I have 5x25L containers for RO I top up through the week to keep a reserve and that takes up a load of space, and then I have more for storing mixed salt water too...
 
If you've got outside space, you could fill up a water barrel gradually during the week and then do the change at the end. A long hose and a pump means you don't have to carry around buckets.

Will it be high tech? You could look at low tech and lower water changes.

Or course a bigger tank doesn't have to mean more water - you could double the size of the tank but keep half emersed if that appeals.
 
I have the same water parameters, even harder water and I have a nice group of 12 cardinals brighty coloured living in my tank for 1 year without any losses. They won't breed for sure, but I think it is a good indicator of health. Good water quality and good regular food is the way to go... However I have to admit that this is the first time I have non hard water fish. Yes, fish is the only constraint.

With plants I've never had problems, if I haven't been successful with some species, it has not been due to my hard water but to my poor skills. I'm sure you know all this but there are a few things that made me keep on using tap hard water instead of switching to RO and having not very large tanks:

- it's easier, so it more likely I will be doing large relevant water changes without being a pain regarding the time spent, water production or storage
- I live in a flat and in the Mediterranean coast, so that means water scarcity, low probabilities of having enough rain water, not able to store much water...
- if I buy an RO unit I would have to buy an small pump to increase the efficiency (I don't want to hear about 4:1 ratios, water is expensive here) and they are not cheap. Filters have also to be changed more frequently with hard water.... So not really cheap, both the investment and maintenance. When I calculated it I realized I preferred to use this money for.... A new tank? :)

If you still want to use RO water, my guess is that you should invest in a very good RO unit that produces little waste and lots of water/hour, so there is less need to store and you won't pay expensive water bills. Or design in this new room refurbishment a cupboard only for this. It's easy to find (but not to move) 50 liters plastic barrels, and three of them could be enough.

Jordi
 
Thanks for all the replies.

My RO unit is very efficient, with virtually no waste water. This is because I am using a 130 PSI booster pump, and I have piggy- backed two 75 GPD membranes in sequence. The waste tap from one membrane runs into the input for the other membrane. So waste is not an issue at all. The only issue is storing the water. It's easy enough to pump the water into the tank, it's just a question of where and how to store it.

I'm considering just sticking with my 125 and maybe buying another marine tank to go next to it. I'd love to keep seahorses.
 
It is pretty simple to install a 6mm RO ball valve on you tank rim, you then just run the RO tubeing from the unit to the tank.
After that you have a choice to sython or pump the water from your tank to waste.
I use a long lenth or air line to syphon out the water straight down the bathroom sink waste (it is permanently plumed in to the waste pipe) and let the ball valve top up the tank, the air line won't run any faster than the top up so it is semi auto and of course the tank level will never change.
In my case I run the syphon for about two hours a day which is about 10 gallons.
 
Clive, cardinals do not thrive in water that hard. I know they don't. They only started properly colouring up and getting full rounded bodies when I switched to RO.
 
Feed lots of live food and Bobs your uncle.
I've had no trouble with cardinals and other tetras or soft water fish thriving in water similar to London tap water. As far as high NO3/PO4, please...

P. transvestitus - a notoriously difficult soft water fish. 750 microseimens, GH 26+, KH 15 + 5X EI dosing.
8394076339_cc451998f6_c.jpg


Marble Hatchets in the same tank
8395168154_a54f3a7b15_c.jpg


Ram in the same tank.
8395170302_ac9c1f3ddb_c.jpg



Nutrition, clean tank and healthy plants are the keys. I see no reason you cannot mix your current RO reservoir with tap and have them looking nice.

Cheers,
 
Thanks Clive. I will consider going the tap water route. But I am reluctant to switch from RO after many years of having full control over water parameters and being able to keep the TDS as low as I like. I just had a lot of problems before I switched to RO.
 
My water parameters are very similar - living in Bucks, and many so called soft water fish have thrived in the tap water...it's exactly as Clive says.
Also you might want to consider that unless the fish are actually wild caught specimens, they may well have been bred and kept in similar water conditions anyway. I know for a fact that a London breeder used to supply a LFS with Cardinals and the like.
 
Sacha said:
I keep Cardinal tetras. My tap water is TDS 350- 400, KH is above 10, GH is about 20.
Click to expand...

Blimey I have never heard of anyone with water parameters like this before!! I live in Wales so I am very lucky. I have got Discus and 40 Cardinals in my tank and I use tap water through a HMA filter which has the hosepipe connectors so I can run it straight from the kitchen tap into the tank. My tank is 400 litres and I change 200 litres once a week. The tap water by itself is very soft 0KH and 0GH and 90 TDS, I only use the HMA filter to take out my he chlorine and any heavy metals. Water change takes about 1 hour including glass cleaning and pruning or maintenance.

Steve
 
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