Biocide or additive for gate coolant loop?

[Ryan Gallagher]

Do you fine folks have any recommendations for additives with biocide properties for 35mm Century coolant loops and tanks? Bleach?

Alas here we are again. A couple years ago I overhauled our Century cooling plate loops, new tanks, new hoses, new fittings, deep flush with radiator cleaner and diluted white vinegar. Started "fresh" with RO water (cause it was easier to come by than DI water in quantity), plus the recommended anti-freeze ratio.

While the effort did seem to cause the tanks to last longer before growth and slime started to appear, especially compared to my predecessor's methods of just tap water, it still wasn't as long as I had hoped, we are about 15mo in and have growth again!! Lots of stairs involved to do full water swaps now that we aren't using tap water, trying to stretch that timetable out and avoid shit growing in there.

I've seen the sealed "radiator" style mods, some employing CPU type water coolers and pumps. I'm not quite there yet, but it is more tempting now. Was hoping just to kill things and better prevent them from growing next purge and refill.

These were food grade tubs pretty well sealed to outside air, wire-grommets, butyl tape, quick fittings with o-rings, the whole 9 yards. I had previously shared my parts list in another thread here:
https://www.film-tech.com/vbb/forum/...4006#post34006


YUCK

TankGrowth.jpg

PS, the antifreeze was green. That is not the growth, just the floaters (and a general sense of it being more cloudy now).

[Ryan Gallagher]

Maybe something like a biocide designed for low temp low flow under-floor water based heating systems?
https://sentinelprotects.com/uk-en/c...s/g+c+p+a+view

Only not sure if it would be compatible with the antifreeze. Which I prefer to keep now that Texas has experienced hard freezes combined with major power outages.

[Josh Jones]

I've never seen anything but water in them. Aren't you running super lume's? Isn't water cooling kinda overkill for that? I never really saw the appeal of water cooled traps anyway, unless your running really big lamps.

Josh

[Ryan Gallagher]

I've never seen anything but water in them. Aren't you running super lume's? Isn't water cooling kinda overkill for that? I never really saw the appeal of water cooled traps anyway, unless your running really big lamps.

Josh

We run 4.5Ks in Super80s. Right on the cusp of justifying cooling. They were here when I got here, so just maintaining status quo. I do like how cool they keep the trap for cleaning between reels!

Antifreeze mix is recommended in manuals, A) so drive ins don’t freeze and explode hoses, and B) because it is supposed to have some biocide and anti-corrosion properties. We can see not enough biocide apparently.

i am also tempted by a UV sterilizing lamp mod.

PS read bleach is a no-go, corrosive to brass, which the trap cooler is likely made of, as well as some of our submerged pump fittings.

RO water might have been our poor choice, actual distilled water would perhaps have fared better. I said DI in the OP, I meant distilled, not de-ionized water.

[Josh Jones]

We use regular filtered water/glycol mix in water cooled solid state transmitters. I had read about some people running DI water for the mix, but It was too difficult to find in quantity near the sites we maintain. Never had any issues with stuff growing in it, but it is also a pressurized system closed off from atmosphere, and the entire mix is changed every year or two.

I didn't realize you were running lamps that large. I think the rule was anything over 4K could benefit from it, but with modern reflector cold coatings, it likely doesn't make near the difference as in the carbon arc days.


Given your situation, I'd switch back to tap water, and change it more often, maybe every 6 months and add a little bleach to discourage growth. You don't need that much, perhaps a cup in the water.

Josh

[Dave Macaulay]

Those barrel things are nasty. Glycol mix was better than water but would form jelly blobs eventually. We did go to closed loop radiator/fan units for the 7kW consoles as the barrels got pretty hot.

[Randy Stankey]

I had read about some people running DI water for the mix, but It was too difficult to find in quantity near the sites we maintain.

How much water would you need?

You can buy DI water in 55 gal. drums. They weight just under 500 lb. each. You can carry two of them on a hand truck.
Depending on what grade you buy, it costs a couple hundred for a barrel. You can get it in 275 gal. totes, as well. That's about the size of a forklift skid and weighs about a ton. It'll cost you about a grand, plus a deposit for the container.

[Josh Jones]

How much water would you need?

You can buy DI water in 55 gal. drums. They weight just under 500 lb. each. You can carry two of them on a hand truck.
Depending on what grade you buy, it costs a couple hundred for a barrel. You can get it in 275 gal. totes, as well. That's about the size of a forklift skid and weighs about a ton. It'll cost you about a grand, plus a deposit for the container.

The systems we have probably hold about 15 gallons. Given the short life of the coolant, we just elected to use regular water and change it every year. The domestic boxes are recommended to change coolant annually. The German ones are recommended a change every 5 years.

Josh

[Randy Stankey]

How fast would you use a drum? While it won't go bad, the longer it sits, unused, the greater its chances of becoming contaminated or spilled. You would have wasted money that you could have spent elsewhere.

Save yourself some money! Just fill a few clean buckets with spigot water and let them sit out for a few days. You don't need ultra-pure lab grade when garden hose water is all that's necessary. Right?

[Ryan Gallagher]

How fast would you use a drum? While it won't go bad, the longer it sits, unused, the greater its chances of becoming contaminated or spilled. You would have wasted money that you could have spent elsewhere.

Save yourself some money! Just fill a few clean buckets with spigot water and let them sit out for a few days. You don't need ultra-pure lab grade when garden hose water is all that's necessary. Right?

Yeah I'm inclined to think DI water is overkill in this situation. (Although Distilled or DI are generally the recommendation). Plus there are our 6 flights of stairs to consider. I'm willing to tote 5gal style water cooler bottles once a year or less, but anything more frequent than that and it becomes a burden, especially considering we might have shown only a handful of films between changes. I can get Distilled in that size but we have to pick it up from a local dealer. RO water can just be refilled at the grocery store. 55gal drums, although *maybe* cheaper, involves an extra transfer step into something luggable, not really interested.

Ultimately I don't think the water type is really to blame, most processed water is "sterile" from the start. It is really about the loop design, the fact it is so low flow (growth enjoys stagnant areas), and the fact we show 35/70mm so rarely, so most of the time it is just sitting there not circulating, trying to grow things. The tubing size in the trap cooler itself is also to blame, very narrow, like 1/8th... so definitely the flow constriction even with decent pumps and larger tubing outside.

My easiest thoughts are to change which circuit the pumps are on so they can be left on 24/7, at least discouraging growth within the tubes and cooler itself. And then the additive thought to clear up this batch and/or treat the next batch. There are pond and pool clarifiers, enzymatic cleaners, and other coolant treatments to consider. All of which would be easier to judge compatibility if we were just running water and not water+antifreeze. Or add the UV light sterilizers which act as clarifiers, the aquarium/pond community cites them as pretty effective, and they are relatively cheap ones too.

My only worry about leaving the pumps on would be if there is a fitting or tubing failure while no one is in the booth. Pump would just empty the tank onto the floor!! I do have the two older pumps still... maybe just adding them to the tank as "agitator" pumps would be a thought... only those ones stay on, but are not connected to the outside world.

Randy, you might be right that "easiest" is to just go back to tap water (which we have nearby in the booth bathroom), and just treat it or change it more often. Sometimes doing things "correct" is too much work!!

Thankfully at 4.5K our heat-sink tank size is not a concern, not running films all day like the old-timers. ;-) But I do see the benefit, especially for 70mm when our heat shield glass is not installed (cause we still use the spreader lens, for now). I'll give this system a few more seasons before I give up and try to build a sealed active radiator version or switch back to frequent tap water changes, would hate to tell the boss we should rebuild again when we just spent money on all that a couple years ago.

[Ryan Gallagher]

The plus side to the anti-freeze mix was I didn't notice any corrosion starting on any metal fittings, unlike the old tap water system which definitely did have corrosion.

There is probably no perfect system. Even with treated water, there is still condensation that occurs on the walls and lid because the booth is so cold, and that water will be untreated and those locations did have some growth starting on them. A UV-C lamp (non enclosed style) might mitigate that. But they are most effective killing things very close to the lamp, hence why most designs flow water around the lamp via an enclosure.

[Josh Jones]

A friend of mine that does cinema service for many years said he used water bed treatment for his gate coolers.

Josh

[Ryan Gallagher]

A friend of mine that does cinema service for many years said he used water bed treatment for his gate coolers.

Josh

Hah, I never would have thought of that industry. Interesting suggestion.

[Jim Cassedy]

We've got 2 Strong Highlight II consoles running 4.5kw Xenons for our
35/70mm JJ's here. Each has one of these little "radiator & bucket" water
circulators for gate cooling. I think they hold about 1½ or 2 gallons each.
I've always filled them with distilled water, and I remember someone
(it might have been Sam Chavez) recommended putting no more than
2 drops of dish-washing liquid in each one. ( "If you see soap bubbles,
you've used too much", I remember him telling me.) The covers must
fit pretty tightly, because I check them every few months, & there's
almost no evaporation. Once a year I give the whole system a good
flush and replace the water.


JJ_Cooler_2.jpg

(Neither of these are my units here. In fact these two coolerthingys are
separated by several thousand miles. One was in the HATEFUL 8 venue
I worked here in CA, and the other one was in San Antonio,where I was
sent for DUNKIRK. But they are identical to the ones I have here.
(except mine are cleaner! )
JJ_Cooler_1.jpg

[Ryan Gallagher]

Nice pics. I assume there is still a submersible pump in the bucket, and the radiator is the first stop for the warm water after the projector?