Tap water bad for pump?

[Lope]

I recently had to replace the coolant in my rig. Because my rig is so ridiculously heavy and such a beast to do anything with (40KG), I ended up just flushing it with tap water, and then leaving tap water in it.

The first time I filled my loop, I removed the tap water from it by blowing on the pipes, then I filled it with distilled. Obviously this puts loads of bacteria in the water. (I had 7% antifreeze, and got lots of growth and air in my loop and it finally choked after about 20 months)

So although tap water contains more minerals for bacteria to eat, I figured its better than blowing the tap water out of the pipes. The only other way I could do it is flush the loop with a few litres of distilled, flowing down the drain. This doesn't suit my poket.
I should mention that the tap water we get is very soft.

When I refilled it a few weeks ago, I made damn sure there wasn't any air in the loop. And it was really quiet. But now the pump is humming noticably. I'm wondering if the minerals have caused wear in the impellar...?
Its a little Uno 5W 320L/h 1.2m pump, mounted between foam in a PVC res, sitting on bubble wrap.

Also I should mention, part of the appeal of just filling up with tap water is that its so damn easy! It can be done fairly quickly, and then you've got a fresh loop of water, no nasties in it, toxic, environmentally unfriendly chemicals. It should last a good while. Next time I have to flush my loop, I'm going to paint most of my pipes black.

I dont know about mineral deposits. Thats something I will find out

Also the chlorine in the tap water is probably pretty good for keeping the bacteria under control.

[BGP Spook]

I don't think the tap water will kill your pump, though I am not sure of your local water quality.

I am having trouble finding you pump(maybe I am brain dead ). Could you give some more information about it? All the Uno pumps I am finding are much too big to be what you intend.

Your water being soft(which is good, less scaling) doesn't tell me a whole lot other than you likely live in an area where the ground (your bedrock specifically) is low in calcium and magnesium.


Their are two reasons for wanting to use distiled water.

1. It keeps biological activity to a minimum.
2. It is better at fighting corrosion than tap water, generally.


How much is the distilled water per liter in South Africa?

Where I am four liters can be had commonly for $1 USD (~8 Rand).

Unless you need more than 20 liters I would stick with distilled water.


Painting the outside of your tubing, assuming it was clear to begin with, should slow down bio-growth.

[Lope]

Hmm, it was more convenience than cost.

From a drug store (we call em chemists) it was about $1.80 for a litre. my system holds about 3L. I had only bought 5L, and was using an auxillary 30W pump to help me fill the system. The water was flowing fast and furious, splashes etc, case had to be open so i could have access to the PC's resevior and pump so i could shake it to get the air out
After i got it all flushed out and filled up and the air bleeded, I just thought "f* this. this is good enough"

[Butcher]

Tried an auto parts store? You can often get distilled much cheaper from them (it's used for topping up batteries).

[Pyrotechnic]

If it's the typical mag drive pump meant for aquariam or pond use like Eheim pumps are, then it's meant to handle water that isn't tap water quality, as long as you arent sending rocks and sand through the pump. However, I tend to think that antifreeze may extend the pump of the life even more since it prevents buildup of grime in the water and it has sort of a lubricating effect on the pump, especially in a closed system with mixed metals like that. Any plain water will turn nasty and rot your system away if you leave it in long enough. Aquariums and ponds dont have to worry about galvanic corrosion and such since the water has to be kept decent enough for fish to survive.

[Butcher]

Most pond pumps can pass sand and fine gravel without issue as it happens. Not a good idea to have any in your water loop though.