Auto Water Change ideas???

[michika]

I have plans to encorporate one into my new system, so I'm tagging along.

Tentatively we've planned to do ours with solonoids, and controlled either by our RKE or by a separate system.

[banditpowdercoat]

I am trying to invent a good way to automatically keep the Sg in the tank at a stable level. The Auto change would be easy if there was a reliable way to add salt to the tank. Like stated, just drain some, add RO water and then the proper amount of salt.

Presently, Electronic Sg meters are to expensive for my plans.

[sphelps]

If you're going to do something like this keep it simple. It's not hard to set something up where all you have to do is add a consistent amount of salt on a weekly bases and monitor salinity on a monthly bases. If you can't do that then I'm not sure what to say, after all you still gotta clean the glass right?

If you get into complicated systems with multiple pumps, solenoid valves, float switches, and timers or even hoppers you're not only introducing multiple sources of error but multiple sources of failure which is something you want to avoid.

[banditpowdercoat]

Originally Posted by sphelps

If you're going to do something like this keep it simple. It's not hard to set something up where all you have to do is add a consistent amount of salt on a weekly bases and monitor salinity on a monthly bases. If you can't do that then I'm not sure what to say, after all you still gotta clean the glass right?

If you get into complicated systems with multiple pumps, solenoid valves, float switches, and timers or even hoppers you're not only introducing multiple sources of error but multiple sources of failure which is something you want to avoid.

I need to set my tank up for 3 week sustainability. Sometimes cant trust the hired caretakers

[sphelps]

Originally Posted by banditpowdercoat

I need to set my tank up for 3 week sustainability. Sometimes cant trust the hired caretakers

So do a water change every three weeks. I have a system setup on my tank similar to what I described earlier but I have to manually activate the pump, this way I can do it whenever I'm available. Takes about 2 minutes to change 10 gallons and I don't have to have premixed water ready prior to this. Best of all the hole system is just a pump on a switch and bucket of salt with a cup

[sphelps]

If you want to keep a premixed salt storage tank then there is another fairly simple system you can employ.

• You essentially have two top off systems, one for fresh water and one for salt water.
• The fresh water top off works with a slow fill principal (slow pump or restricted solenoid valve).
• Saltwater top off works with a fast fill principal (large pump from storage container).
• Float switch for fresh water top off is located at standard height to maintain standard water level in sump. Should be controlled so water level remains fairly constant 24/7.
• Float switch for saltwater top off is located slightly below the float for fresh water.
• A pump on a timer pumps water out of the sump to a drain on a certain schedule to remove the desired amount of water.

Now the idea is the fresh water top off maintains the water level in the sump so the saltwater float isn't triggered from evaporation. However when the drain pump is activated the fresh water top off will be too slow to keep up so the salt flow will trigger and since it's fast fill, will top the tank back up before much fresh water is added. You'll also want to maintain the salinity of the storage tank slightly higher than the desired aquarium sanity as some extra fresh water will obviously be added every time saltwater is added.

[BC564]

Im using a PLC , solenoids, and a pressure transmitter in inches of water column (4-20 ma)....premixed salt water tank, RO tank for top off, 3 RTD inputs for temperatures (of all 3 tanks), pH probe input, etc..... I always use the same salt and know the amount of salt needed to make 25 litres of salt water, but I'm pretty sure I can be there for the actually test of the SG.

[wolf_bluejay]

What I have at the moment is a 30 gal tank for mixing saltwater, and a feed off my pump that runs to my basement drain. The mixing tank has a power head that has a "closed loop" and a feed to the sump. To do a water change, I just open the valve to the drain and pump out 20-30 gal, close that valve, open the one from the mixing tank and pump in until I'm back up to the proper level.

What I was thinking about doing is this: drill the sump just a smidge about the normal water level (and ATO float switch level) and pump in a bulkhead straight to a drain. Then putting the pump from the mixing tank on a timer to run for a few minutes each day. The water level would rise in the sump and almost the same amount of water I pump in would overflow into the drain. This would allow for my existing ATO to work as normal and the only thing I would have to do it manually refill,and salt and mix the mixing tank. The water changes would happen a few gallons at a time each day.

This risk is that during a power outage or some other event that changes the sump level, the excess water would flow out the drain an be replaced by fresh water when the power returns. But I've only had 1 power outage in 2 years and the fresh water is topped up real slow. So, I'd only loose a few gallons of water on about 250 gal total system volume.

[untamed]

Originally Posted by sphelps

If you want to keep a premixed salt storage tank then there is another fairly simple system you can employ.

• You essentially have two top off systems, one for fresh water and one for salt water.
• The fresh water top off works with a slow fill principal (slow pump or restricted solenoid valve).
• Saltwater top off works with a fast fill principal (large pump from storage container).
• Float switch for fresh water top off is located at standard height to maintain standard water level in sump. Should be controlled so water level remains fairly constant 24/7.
• Float switch for saltwater top off is located slightly below the float for fresh water.
• A pump on a timer pumps water out of the sump to a drain on a certain schedule to remove the desired amount of water.

Now the idea is the fresh water top off maintains the water level in the sump so the saltwater float isn't triggered from evaporation. However when the drain pump is activated the fresh water top off will be too slow to keep up so the salt flow will trigger and since it's fast fill, will top the tank back up before much fresh water is added. You'll also want to maintain the salinity of the storage tank slightly higher than the desired aquarium sanity as some extra fresh water will obviously be added every time saltwater is added.

I think that is pretty clever. You could add an additional, lower level, level sensor and only allow the fast SW fill cycle to initiate if BOTH the upper level AND lower level sensors are low. The only time that the lower level sensor would be low was during the extreme of a water change dump.

This gets around the problem of having the fast-fill trigger every time the sump even goes just a little bit low. It would wait until the sump is dramatically low.

An aquarium controller could handle that kind of logic. I know that Aquatronica could do it, and I assume that Profilux could also handle that.

In fact, while I've not rigged it to run automatically...what you describe is exactly what happens in my system during a water change. Even as I am refilling the WC sump with new SW, RO water is leaking slowing in because the main sump level is low. This extra top off water is insignificant in my system. In fact, because this is "extra" water added, the system returns to normal as this water evaporates away later. (that only works that way because I have 2 sumps)

[banditpowdercoat]

Originally Posted by sphelps

If you want to keep a premixed salt storage tank then there is another fairly simple system you can employ.

• You essentially have two top off systems, one for fresh water and one for salt water.
• The fresh water top off works with a slow fill principal (slow pump or restricted solenoid valve).
• Saltwater top off works with a fast fill principal (large pump from storage container).
• Float switch for fresh water top off is located at standard height to maintain standard water level in sump. Should be controlled so water level remains fairly constant 24/7.
• Float switch for saltwater top off is located slightly below the float for fresh water.
• A pump on a timer pumps water out of the sump to a drain on a certain schedule to remove the desired amount of water.

Now the idea is the fresh water top off maintains the water level in the sump so the saltwater float isn't triggered from evaporation. However when the drain pump is activated the fresh water top off will be too slow to keep up so the salt flow will trigger and since it's fast fill, will top the tank back up before much fresh water is added. You'll also want to maintain the salinity of the storage tank slightly higher than the desired aquarium sanity as some extra fresh water will obviously be added every time saltwater is added.

If you use 2 separate float controls, and set the upper limit for both the SW fill and the FW top off at the same level, then you would not need to up the Sg in the fill water. That is how I was planning to run my setup. ATO and SW use separate start floats, but the same stop float so that no salinity is lost in the tank. Thats the easy part. Its making the SW automatically thats the tricky part. So I dont have to store 50g of SW for changes when I'm away.

PS, If I get this right, I have a feeling those of you with LARGE tanks would love it. 400g+, must get tiresome mixing all the SW up all the time, huh?