[tomasxguty]

Hope somebody can help. We have 650l static tank that has a float valve and filing inlet on the top. Now we have added a bigger 1000l tank that has a transfer pump connected to it. The two tanks are connected via 1/2" hose at the bottom. We were hoping that as the small tank is being filled the gravity will instantly make the level of water in both tanks equal. Instead it takes about an hour for the water in both tanks to be leveled. That makes the RO to work for about an hour on and off. So when the small tanks is full the RO turns off. Two minutes later the water level in the small tank drops and the RO starts producing pure for about 3 minutes and then it stops again 
Is there a way to fill both tanks equally?
How would you go about it if you had two different size tanks?
Thanks

[Don Kee]

You either need a much bigger bore/diametre hose or multiple connection points between the tanks
the water cant get to the other tank fast enough, i.e the r.o is producing faster than the tank connector hose allows water through

[Smudger]

Change to 2" pipe the levels will stay constant

Darran

[tomasxguty]

I am a bit nervous about drilling bigger holes to the tanks. I assume that's the only option to make it work. Thank you for your reply

[Smudger]

I would change over to ibc tanks you don't need to drill holes in them, pick them up for as little as £30

I'll post a piccy later

Darran

[tomasxguty]

Thanks Darran

Unfortunately my  shed is too narrow for ibc tanks. Once I find the 2" tank outlets and a hose I will make the holes bigger...

[Ian Lancaster]

You can do it by siphon.   Make a "U" shape with plastic sink waste pipe and two 90 degree plastic elbows.  Make the legs of the U just long enough to reach the bottoms of the tanks with the connecting bit just resting on the tank tops.  Cut the bottoms of the legs at an angle so the pipes can't "stick" to the bottom of the tanks and prevent water from flowing.  Make the bottom of the U long enough to span across between the filler holes on the two tanks but keep the holes as close to each other as you can.  Fill both tanks then insert the legs of the U into each hole. Unscrew one elbow nut to allow the air to escape and water to fill the legs.  Re-tighten the elbow nut so the U is airtight.  You will probably need to secure the U so it doesn't float up.

Now when you draw water from one tank, water from the other will flow by siphonic action into the first tank till the levels are the same.  The small quantity of air trapped in the cross-piece of the U will be  drawn through by the water flow.

Provided you make sure both leg bottoms are always covered (i.e. don't empty the tanks right out) water will flow either way depending on which tank has the highest level in it.  I had to install a system like this using 3 linked 45 gallon drums for one of our blokes where we couldn't get an IBC into his back garden.

Works fine

[Smurf]

You can do it by siphon.   Make a "U" shape with plastic sink waste pipe and two 90 degree plastic elbows.  Make the legs of the U just long enough to reach the bottoms of the tanks with the connecting bit just resting on the tank tops.  Cut the bottoms of the legs at an angle so the pipes can't "stick" to the bottom of the tanks and prevent water from flowing.  Make the bottom of the U long enough to span across between the filler holes on the two tanks but keep the holes as close to each other as you can.  Fill both tanks then insert the legs of the U into each hole. Unscrew one elbow nut to allow the air to escape and water to fill the legs.  Re-tighten the elbow nut so the U is airtight.  You will probably need to secure the U so it doesn't float up.

Now when you draw water from one tank, water from the other will flow by siphonic action into the first tank till the levels are the same.  The small quantity of air trapped in the cross-piece of the U will be  drawn through by the water flow.

Provided you make sure both leg bottoms are always covered (i.e. don't empty the tanks right out) water will flow either way depending on which tank has the highest level in it.  I had to install a system like this using 3 linked 45 gallon drums for one of our blokes where we couldn't get an IBC into his back garden.

Works fine

Sound intersting Ian but that went right over my head to be honest... Have you got any pics to show what you are on about please as I'm sure others would be interested to see it made and how it works.

[paulben]

Pic please I am interested not sure how it starts to flow without sucking

[Don Kee]

Pic please I am interested not sure how it starts to flow without sucking

It's due to an unbalanced water pressure between the tanks.
Once one tank starts to lose water it has less pressure and so the water (through the pipe) will then move from the more full tank to the less full to create equal pressure (an equilibrium if you will  )
Thats why you fill both with water first, and then get rid of the air in the piping, it then creates that siphon effect as the water will try to 'escape' to the lower pressure (less full) tank until both have equal amounts of water

You'd still want an half decent diameter piping though depending on how fast your ro produces

Its a very good idea to solve the problem! 

[Smudger]

That's how I set up my 4 ibc tanks, shame you can't fit in ibc tanks as they are excellent for storage

Darran

[tomasxguty]

That looks awesome Darran. Thanks for sharing.
Hope it will help other people too...

[tomasxguty]

Your idea would work for us Ian. Would you be able to post a simple drawing please? Also would it work with 1.5 inch hose instead of a pipe?

[Ian Lancaster]

There you go! 

The pipe is standard kitchen sink waste pipe with 90 degree elbows - get it in any diy shop.

Fill both tanks, slacken off one of the right angle connectors, insert the "u" shaped pipe assembly into the tanks, allow the air to escape then tighten the connector again.  You might need to tie it down to keep it in place.

Now when you draw water from one tank the water from the other will flow through the pipe to even up the levels.  Just don't let the level drop below the bottom of the pipes as you will break the siphon and then you have to fill each tank separately again and repeat as above to re-establish the siphon.

[paulben]

Thanks