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View Full Version : Simple Auto Water Change System


Doahh
07/03/2008, 06:30 PM
Parts Needed
2) Aqualifter Pumps
1) Timer with 15 minute increments (like the little buttons)
http://www.hydroponics-hydroponic.com/images/000_0515.jpg
2) .5 GPD Sprinkler Drippers
1) Drain
1) Splitter to plug both Aqualifters into the single timer
1) Water Source
TUBING!

Now to set it up:

Get both aqualifters and plug both into the timer
Attach tubing and the .5 GPH dripper to the end of the output
Put the inlet of one in the Fresh SW and the out put of that one DOWN-CURRENT of the Bad Water inlet
Put the Bad Water out near your drain/ outside through the wall like I will
Now if you want to change 1.5 GPD take that figure and you will need the pump to be on for 3 hours throughout the day. Set the timer to come on for 15 minutes every hour for 12 hours or figure out your application. You could even use the 1 GPH drippers to have it on half as long.

Thanks
I will be using this on my next setup and will get pics then

Doahh
07/03/2008, 08:30 PM
Thoughts? Ideas?

Doahh
07/03/2008, 09:53 PM
This would work wouldn't it?

areze
07/03/2008, 09:57 PM
problem with it is a few fold.

first, continuous water changes are very inefficient. if you change 1% of the water, then change another 1%, you are 1% of your 2nd 1% is clean... doesnt sound like much, but your 10th 1% is 10% clean; if your total batch is 20%, your throwing away alot of clean water, and more to the point, your removing less dirty water. your best water change is to remove all the dirty, and replace it 1 after the other in 2 stages, not at the same time and not alternating. drain it all, then fill it back up. no waste.

next up, if Im understanding it right you have opposing pumps one draining, 1 refilling. if the 2 do not pump at the same speed(and due to head restrictions I cant imagine they ever would short of massive tuning, and still not gaurentees) you can end up pumping the sump dry, or overflowing it.

bottom line, you would need a large volume of water in your tank's loop, a volume which you can shut off, drain and subsequently refill. thats about as good as it gets.

my plan on my new setup, I have 50g of filtered water on hand at all times. for water changes I pop open a valve and it gravity feeds to a mixing bin. the mixing bin is 54g, my hope is to simply dump a 50g bag of salt into this bin, open up the valve, fill it with water, turn on a mixing pump and heater for a day and then later open another valve to drain 50g from the tank and subsequently replace it.

its relatively simple...

what makes it very not simple is the fact that my top off section of the sump, the one that can fluctuate when the tank evaporates or is drains; is not 50gallons, no where near it infact(Id guesstimate 5 or 10gallons at best). so I have to disable the sump and drain the water from the display for a water change... which I dont like. Id like to make the 50g water change tank part of the display system somehow, pipe water from the sump return compartment, to the mixing bin, and overflow it back to the sump. then for a water change, I turn off that pump; discard the water in the bin, mix new batch, and turn it back on and mix with the system water over time. Ill figure it out eventually... my mixing bin is a rubbermaid, which doesnt take to an overflow very kindly. a standpipe would work though.

areze
07/03/2008, 10:05 PM
btw, Im not saying your system couldnt work... the 1% water changes are inefficient. no way around that, but its only money to be honest.

the way I see it, you would need some sort of salinity monitor. and an overflow on your sump. then you can just pump a steady stream of salt water into your circuit and let it overflow continuously to your drain. but then you cant topoff correctly with an auto top off since the salt water would technically be doing that for you(while raising your salinity). so you would need the salinity probe to somehow control a fresh water supply to add it as needed to maintain your salinity...

I just made things very expensive. but thats the best I can come up with.

Doahh
07/03/2008, 10:06 PM
It changes 1.5 gallons per day...
That's around 10.5 gallons per week on a 90 gallon. That's not very efficient?

The drip rates are FIXED at .5 GPH because of the sprinkler drippers.

Fresh Salt Water will go in practically injected into the return pump.

It couldn't possibly run the sump dry or overflow it because at most it will take out .0125 gallons of water every cycle. I have mine go for one cycle every 2 hours

areze
07/03/2008, 10:23 PM
heres an example, based on your numbers.

you are changing 1.6% of your water every day. go off a 7 day cycle for simplicity

option 1, just change 11.6% of your water. its 10.44gallons, done. 10.5gallons comes out, 10.5 goes in.

your system

day 1 1.5g
day 2 1.5g, .024g is previously fresh
day 3 1.5g, .048g is previously fresh
day 4 1.5g, .072g is previously fresh
day 5 1.5g, .096g is previously fresh
day 6 1.5g, .12g is previously fresh
day 7 1.5g, .144g is previously fresh

actually its slightly less, because you are removing prior fresh, it doesnt go up quite that fast. but anyway, of your 10.5g you added, you removed roughly .504g of it... like I said, itll work, its just money, its not OMG drastic or anything, but if it can be avoided... eh I would. another factor, your coing 10% a week, there are folks doing 20 or 30% a week, and some with much larger system volumes as well, you can end up throwing away 10 or 20 gallons of water a week, and that would hurt in those situations.

if it works for you, rock on; but its not quite PERFECT. if you could reset it to do it all at 1 time in the week rather than daily it would be alot better(I still dont like having drips match up to a pump rate; I presume you check it and by going daily can easily correct it)

maybe Im busting your system if it were all at once each week. plus it requires a 10gallon margin to be removed and replaced; which like in my problem, you probably would have to drain the display to get.

Elite
07/04/2008, 12:30 AM
My friend uses Littermeter III with the 2 pumps. They turn on and off 150 times a day. That is 150 small WC a day. His tank is great. Small WC per day does work.

jerryz
07/04/2008, 07:56 AM
In terms of truly consistent water quality the continuous water change has a lot going for it. It's disadvantage lies in economics not in potential stability benefits. I'm in the 3% daily water change camp and always have great water params. Could I ignore my tank in terms daily water changes and have it do as well? In truth the answer is probably yes. It's a mature tank but why risk it if I don't have to.

Paul_PSU
07/04/2008, 08:08 AM
Smaller more frequent water changes would keep your system much more stable, would it not?

areze
07/04/2008, 08:20 AM
that it would

Doahh
07/04/2008, 11:03 AM
Awesome.
That's what my Research pointed to but I was waiting for a few more people to agree with it

jcollins
07/04/2008, 01:59 PM
I always have done smaller weekly water changes. I thought about doing larger monthly changes when I finish my new system. I haven't had any problems but I want to see if I can tell a difference.

Elite
07/04/2008, 02:55 PM
This is the tank I'm talking about.. Hopefully he doesn't mind I post the pic :D ..

The only bad thing about auto WC is cost..

http://i85.photobucket.com/albums/k60/Elitehvc/Tong%20tank/120Gtank.jpg

Kentanner11
07/05/2008, 02:14 PM
<a href=showthread.php?s=&postid=12877220#post12877220 target=_blank>Originally posted</a> by Doahh


The drip rates are FIXED at .5 GPH because of the sprinkler drippers.


Brilliant!!! I cant believe I didnt even think of that! Great job!!!
:rollface: :rollface: :rollface: :rollface:

coralfragger101
07/05/2008, 02:22 PM
I find it hard to believe that the sprinkler drippers are accurate.

I believe that they are probably close enough that this will work but over the long haul I believe it will either raise or lower your salinity level.

So - simply keep an eye on it. If it changes the salinity something like 1 ppm over a 3 month period - no problem. Just make an adjustment for it every once in awhile. If it changes your salinity over the course of a couple of days, I'd trash the idea.

Doahh
07/05/2008, 02:35 PM
Yeah I already check the salinity daily... It's too easy to not do with a refractometer