Slime in the tubes including a long-term test – Particle filter, do-it-yourself filter and the follow-up costs of PVC tubes

1 - If you like soft tubes 2 - Normal commercially available built-in filters (inline) 3 - DIY monster filter 4 - Rinsing, cleaning, summary and conclusion

No, it is not a contradiction, but transparent plastic tube (usually PVC) is cheap to buy, but really expensive in follow-up costs. Who can, prefer to go for hard tubing or such nice things as EPDM or Teflon, but there are also situations where you end up torn as to what it should be. And many a person is afraid to take anything other than PVC tube for fear of their own craftsmanship. You can do that, but you have to follow a few important rules. This information and especially my particle filters shall be the subject of today’s article, we’ll do the rest later.

The initial situation: annoying suspended particles and plasticizer slime

Only that does not always work with the opaque EPDM and also in my case, where I always have to check what is bubbling in the system and where there may still be an air bubble hiding. Softer PVC tubes make perfect sense for me. Since I use meters of flexible tubing here in the lab and have to rebuild everything very often, I have made a virtue out of necessity and deliberately never renewed a small part of the tubing system (approx. 40 cm on the chiller) in the last 5 years. I was curious how such a tube ages – despite permanent coolant care.

That went until today, then the ancient tube had to come out once. Why the end user has to be careful and what you can do at least against the slime formed, I’ll show you today. First, we marvel once at the feces-colored patina of the two approx. 40 cm long PVC connectors at the inlet and outlet of one the chillers, which have not yet been replaced out of curiosity and convenience. The plasticizer secretly evaporated on the inside, and everything that was too lazy to flow on settled on the rougher surface.

In addition, there is a system that has been relying on tubing for at least 4 years and where I replaced the coolant at least once two years ago. This almost silent computer is located in the audio area and is very often in use. And in the meantime so much stuff had settled there inside that I simply tapped the good piece and filtered the outflowing garbage. We will admire that in a moment, too, before I write very briefly about the causes, show alternatives and introduce you to my filters, one of which is a huge do-it-yourself solution and can filter away suspended particles down to 5 μm.

Of course, no end customer needs that, but I do. If you knew how many poorly galvanized coolers arrive here and what still comes out of some parts like radiators despite previous pressure flushing when they have been in operation for a longer time – you could really lose faith in the producing mankind. In the chiller, I have a special outlet at the bottom and also a way there, similar to a washing machine, to drain off sunk particles and slime instead of lint. However, this only works after a longer downtime.

I already wrote in the introduction that the tube can be really expensive. After all, the larger a system is, the more coolant you need. And since I also do a lot of comparison measurements here, it always has to be the same Coolant and, above all, clean. Otherwise, the coolers under test will be clogged faster than you can say pug. And yes, such a 5l canister Double Protect (DP) Ultra from Aquacomputer already costs about 35 euros and a little more. A chiller holds around 7 liters inside, plus another large expansion tank and meters of tube per system. It quickly becomes 3 or up to 4 canisters per system and I even have two chillers in use. In addition, two normal, flexibly equipped laboratory water cooling systems. If you want to get an impression of how such a day of filling starts as a round trip (on the picture above): Then there is a small fortune on the wall for tipping every time…

Well, I take, depending on the application, different liquids (not only the DP Ultra) – whereby one of the systems uses only pure osmosis water from Alphacool without additives and another, on the other hand, deliberately relies on blue Coolant (also Alphacool), because you can see leaks (on white paper underneath) best. And with such finished products, the rule is always: never mix or stretch unless it is expressly permitted. Otherwise, with a bit of bad luck, the broth will tip or unwanted flocculation will occur. And the subject of mold is a whole other story in the end, which I’d like to leave out today. It would simply be too much and there are already enough suitable specialist forums on the subject of water cooling. Today it is primarily about filters, also a nice topic.

Ttube who do not dare hard tubing

Now you know why I use PVC tubing in the lab despite all the disadvantages (and also against my better judgment). But what does the anxious do-it-yourself builder take if he absolutely wants to rely on flexible tube? Maybe because he wants to swap components more often? Yes, you can reduce plasticizer migration as long as you can stay around 30 °C water temperature, or even 35 °C at the peak.

PVC is a thermoplastic to which additives must always be added in order to obtain the desired or required properties in the final product. The softer the tube, the more plasticizer was added as an additive.  If you really do not want to do without PVC tube, use the stiffest possible tube, which can be bent just so. The trick then is post-processing, because as a thermoplastic, PVC can still be deformed under careful heating, and the tube largely retains its new shape after cooling. You can also use BPA-free tube, but unfortunately it costs a little more. However, outsourcing is not completely out of the question. And coolants containing glysantine are ideal for attacking all tube surfaces inside.

Tubes made of EPDM (ethylene propylene diene rubber) are better. Things like rubber and some other plastics are already elastic enough in our normal temperature range (between 20 and 50 °C) and therefore also no need for an additional plasticizer. These compounds are also called elastomers, although here, too, one or the other additive can of course be mixed in. NorPrene is also often used in advertising, but it is a brand name (like Teflon) for a composite of EPDM and PP (polypropylene).

Why I don’t use EPDM for the long hauls like I do in the private sector? I have very many different connections in the circuit. EPDM cannot be securely fastened with normal grommets for everyday laboratory use, as the tube quickly slips out of a screw-on grommet if the pressure is too high or if various bends occur. In the end, NorPrene tube in combination with tube nozzle and spring tube clamp would probably be the safest option, but for me it’s too much work. However, the end user should be really well served with it (and may even be able to omit the spring tube clamp). Other things like Teflon tube are expensive, but are quite good. And there are such tubes even in white.

And right now we have arrived at the chapter value preservation for our expensive BPA-free tube and the even more expensive filling, turn the page once please!