DIY Auto-Top off with Solenoid

[Lunchbucket]

yeah the waste still flows. for me it is nice that i don't have to watch it so close..that i don't flood my kitchen. i watch it just not that much...so i won't waste much even if i do run waste w/out ro/di.

also, on the topic...could you put it in line w/ the inlet of water to have it shut off?? or would there be too much pressure etc?

Lunchbucket

 

[jarhead]

...with the solenoid on the outlet of the RO/DI doesn't that mean the waste is constantly flowing, 24/7? I know it's not much but it adds up doesn't it? Also I thought/read that a membrane will not last as long if there's constant pressure on it...

I don't want to take this thread off topic, but my post in the Reef Discussion forum will answer your question. Pay particular attention to the reply on the 2nd page by The Gang from ARS.

 

[Zephrant]

DD- I have an pressure cut-off regulator on the input of the RO unit. When the good water stops coming out of the RO (due to the tank being full, and the solenoid closed) the cut-off stops the water going in to the RO/DI. No continuous running, no static pressure on the membrane. This device can be retrofit to any RO/DI unit.

I quick search of McMaster-carr reveals that the solenoid is rated for up to 150PSI. Since normal water supplies rarely go over 70psi, it should be fine.

I'll trade you some speed-fits for a few bags of southdown. I'll pay shipping on the speed-fits, if you ship the SD.

Zeph

 

[Nammy]

Thanks for the clear instructions. Off to Home Depot I go.

 

[Lunchbucket]

Zephrant - where you get that one to hold back your inlet water??

Lunchbucket

 

[Zephrant]

LB- Aquatic Reef Systems, it came with the RO/DI unit. It is a mechanical pressure device. When the output pressure builds to within 20psi of the inlet, the inlet pressure is shut and held off.

Zeph

 

[Scleractinian]

Float switch guard

Float switch guard

Has anyone found any need to fab some kind of perforated guard for the float switch? If so, what dod you use?

 

[ShapeGSX]

I've done the exact same thing in my own tank. The only difference is that I didn't use a float valve. I have two float switches in series. One sits mounted inside a 1.25" PVC end cap mounted on a 1 1/4" PVC pipe with holes drilled in it. The pipe keeps algae from growing inside the pipe, and around the float switch.

The other switch is mounted higher in the sump. It is out of the way of the water, so it should stay clean and algae free. It is only there to shut off the solenoid should the other float switch get stuck. I do not have a failsafe for if the solenoid gets stuck.

The solenoid gets fed from my pressurized RO drinking water kit holding tank. The solenoid feeds into my kalkwasser reactor. The oulte of the kalkwasser reactor feeds kalk directly into the sump.

The problem with a float valve setup with a kalkwasser reactor is that the float valve would get crusted over with calcium eventually, and probably wouldn't provide much of a failsafe.

I may add a second solenoid in series that gets switched on (closed) when the second float swith gets turned on by the sump water level. That would provide a real failsafe.

 

[schemo]

Zeph,

just a quick question, i plan to get the same soleniod but in 12VDC will the same float switch work with 12VDC? the float switch is rated at 120/220v so i'm figuring that it will work? but don't want to buy something that i can't use???

reason why i'm getting the 12VDC is because they don't have that seloniod in 220VAC and voltage here is 220 in italy.

thanks for the help
schemo

 

[ShapeGSX]

Zeph,

just a quick question, i plan to get the same soleniod but in 12VDC will the same float switch work with 12VDC? the float switch is rated at 120/220v so i'm figuring that it will work? but don't want to buy something that i can't use???

reason why i'm getting the 12VDC is because they don't have that seloniod in 220VAC and voltage here is 220 in italy.

thanks for the help
schemo

I forgot to mention in my previous post that I am using 12V DC to power my solenoid. I got a 12VDC solenoid and a 12VDC power supply. Make sure your power supply can handle the current draw of the solenoid!! My original 750mA supply wouldn't work. I upgraded to a 1200mA supply and all was well.

I decided to go with DC voltage because it should be safer than 110V immersed in saltwater. Not that there should be an issue if it is wired correctly. We stick 110V cords into our tanks all the time (power heads, heaters, etc...). But I felt safer doing it this way.

 

[schemo]

ShapeGSX ,
did you get the same float switch? so then it will work regardless of the power being VDC???

thanks for letting me know about the mA so i wouldn't have to buy two transformers!!!!!

schemo

 

[ShapeGSX]

The float switch will work fine. It is just a reed switch that is triggered by a magnet. The wires don't care if they carry AC or DC so long as the current through them doesn't get high enough to melt something. And with 12V, you are less likely to melt something than with 110V.

 

[Zephrant]

Hey- Shape is right, 12VDC is fine. The only draw backs are the extra expense of the transformer, and potential longevity. 12V contacts simply don't last as long as 120V contacts in relay situations. The 120V circuits have enough voltage to self-clean the contacts somewhat, where the 12v circuits do not.

Considering the contacts only fire a few times a day, it would take years to see a difference however, so again, 12V is fine.

Zeph

 

[schemo]

Zephrant & ShapeGSX,

thanks for the info, i'm going to make my purchase today, it kinda sucks to be here in italy sometimes i always have problems trying to do DIY projects that you guys in the states are doing, it's all about the voltage!!!!!

schemo

 

[tricky]

In my plans is also to make a reservoir in the fish room for water, so I have more RO/DI water sitting on hand for water changes and all. When that is in place, I can use more solenoids and switches to turn on the RO/DI feed when it is low, and off when it is full.

HTH

Zeph

Zeph,
You may want to reconsider how you store RO/DI water. ARS does not recommend using a storage tank for DI water. They have found that algae can accumulate in the storage tank after several years of use, even with RO only water. They reccomend periodic tank replacement.
DI filtered water is very reactive and even more susceptable to any unsterile environment. I have used open containers for makeup water and seen a slime form very quickly. Open storage can rapidly absorb contaminants from the air.

 

[Zephrant]

tricky- Good points. My plan is to build a square 50 gal acrylic tank with a solid top with a large 6" cap (and plumbing in/out) as the only openings. If I want to make up saltwater, I'll open the cap and throw in some salt, the drop in a power head and heater to mix it up. The next day, I'll open the drain on the sump, remove 50 gallons, then let the new water flush in.

So the water will never be "pure" RO/DI water, there will always be some salt residue. Since I loose a little salt to the skimmer effluent, I could throw in a 1/2 cup every once in a while to the makeup water, which would also help the "ultra-pure water is a good solvent" problem.

I could also put a drain on it, so that I could throw in some vinegar water, or if really careful, chlorinate it once a year or so.

I might locate some water-proof electrical connectors, so I could leave the pump/heater in there full time, without having to deal with the cords. Maybe a closed loop, with an inline heater would work well, but I have not seen a cheap inline heater before.

Thanks for the tips- It has helped my planning!

Zeph

 

[Zephrant]

I had a PM asking for some more soldering details, so I thought I would tack them on here.

Soldering well takes some skill, so it is good to practice a little. Here are a few tips:

The basic idea is to get the wire hot enough to melt the solder, not vice-versa. Use a 50 watt soldering iron max. A soldering gun can be used if you are practiced, but it is pretty difficult for a new person to master.

Place something heat-proof under your work, you will drip molten solder on it, and the flux splatters. Use some safety glasses. Nothing like a little spec of boiling flux in your eye to ruin your night.

Use flux, it makes a world of difference. Don't use acid-core flux, that is for plumbing copper pipe. Use electronic flux, as well as solder designed for electronics. Radio Shack or similar carries it, as do most Home Depot type stores.

Twist any loose strands at the end of the wire together first. Dip the exposed wire in the flux before starting.

Apply heat(iron) to the wire on one side, and touch the solder to the other side. When the solder gets hot enough to melt, it will flow in-between the strands of the wire. Remove the heat when the solder flows in. With a hot iron, this step should take no more than 3 seconds.

Check the wire, if there is not solder all around it, try again. Let the wire cool in-between steps or you risk melting the insulation off of it.

When you have the wires all tinned, it gets easier. Put on the heat shrink pieces if you have them now, before you continue. Slide them back out of the way, or the heat from the iron will shrink them before you are ready.

Use a clamp to hold one wire steady, and align the other wire parallel to it and just overlapping the tinned areas. Touch the soldering iron to both wires simultaneously, and remove it in a second or two. The existing solder on the iron and wires will melt and fuse together. Allow to solidify for a few seconds and you are done.

Good soldering skills takes practice. If you know anyone with such skills, get them to show you a few tricks. It can make a world of difference.

HTH-

Zeph

 

[Rocky Mountain Reef]

Hey Zephrant,

Does this kind of wiring/switch introduce any current into the tank? I'm going to do this with a vertical float switch (per Snailman's DIY idea) to run the solenoid, but everything else should be the same with my plan for topoff.


Great post,
Jim

 

[Zephrant]

Rocky- In a word, nope. The closest the power gets to salt water is the float valve. Induced current needs a magnetic coil, or a plasma arc (lights) or something similar that uses a good amount of electricity. The solenoid uses so little, the effects would not be measurable.

HTH-

Zeph

 

[pantinor]

Zeph,

Do you recommend using a 1/2" threaded bulkhead if the float switch is to go through the outer wall of the sump?

Does the NPT tap leak?

I would like to get by without the bulkhead if possible...

Thanks.