Best to avoid all those potential problems, and just going for a minimum of deionised water, it can even be bought at Asda. I will be adding a silver kill-coil to my loop once I get around to fitting it up. This will kill any and all bacteria.
I did put a little bit of anti-freeze in my water tank. Initially filled with de-ionized water.
It helped to reduce the number of small bubbles I was getting when I was starting the laser.
I did put only a little, something like 1/2 litre.
I had to run the pump for a little while (10 minutes) before all the bubbles would male their way out of the tube and into the tank.
Also I was always worried about getting bubbles at the entrance of the tube which is hidden from view on my laser (6840)
Now I run the pump 24h/7, it burns very little electricity and keeps everything nice and clear. This is definitely the best way for me to keep the bubbles out !
I have had my laser for 6 months ish, light hobby use, no growths/slime in the tank. The black tank definitely helps, and I also agree with the previous comments on UV killing capability for the various bacteria/slime.
I have never had a single issue with water bubbles in the tube. Are people ensuring that the outlet is always under the water? I have mine weighted to make sure of it. The pump is also completely submerged. Once I got rid of the air bubbles, none have come back.
Tube bubbles aren't the problem Phil, it's tiny bubles in the mirror chamber at the end that causes tubes to die. It's the nature of submersible pumps that they cause cavitation, hence bubbles.
It's usually worse in cold weather or when there is a big differential between ambient pressure and pumped pressure that causes the biggest problems.
best wishes
Dave
Please note I am not employed by HPC, any advice or recomendations I give are based on my own experience and are not necessarily the same as HPC's. First point of contact on any hardware issues should be with HPC Dave@OpticalPower.co.uk
