Hey

I can't seem to find appropriate info on how to manage gas exchange in a cheap manner.

Can you please share your method of keeping the mycelium growth contamination free yet still managing gas exchange?

I use a passive method with a sealed tub that has two rows of holes stuffed with polyfill. One row is near the top of the tub and another row is near the bottom.

The polyfill keeps the contaminants out while allowing air to move. The theory is that the lower row of holes evacuates the heavier CO2, and as that happens fresh air comes in the top row of holes. Not sure how much of that theory is actualized, but in practice I can say that the mushies are happy with the setup. Also, there are streaks of missing water droplets on the tub wall below the top holes which indicates the downward air flow does happen.

More details here.

hi

lovealls tek is perfect for the type of mono tub he uses. If you use that type of tub then read no further

If you are talking about FAE on mono tubs then it depends on the tub setup, if you have holes at the bottom then block them up with polly fill and keep the lid closed.

If you do a bod tek bods tub tek then the gap at the top is enough.

If you are talking about FAE on pf cakes, all you need a loose foil lid and dry verm protecting the cake and that's enough.

I find that the key to avoiding contams is sterile technique, right conditions and speed of colonisation.

So for example, old syringes (more than 6 - 12 months old) can produce mycelium that is a bit senile, it can be quite a bit slower to colonise the substrait than fresh syringes, slower growth times = more time for contams to take hold. So if working with an old syringe its my advice to just do a few pf cakes with it, get them to fruit and take spore prints and make new syringes, then the new mycelium will grow at its maximum rate.

When making your jars of rye / wbs / oats etc ensure your pressure cook (PC) them for 90 mins at 15 psi, no less, ideally a little longer. let it cool naturally and ideally cover the PC with a bleach / alcahol / peroxide soaked cloth, so any air going in as it cools gets sterilised as much as possible.

Use / make a still air box (SAB) or a glove box (GB). Clean the SAB or glove box with bleach then peroxide then alcohol every time you use it, using fresh paper towels each time. Put a paper towel soaked in peroxide in the SAB / GB. Keep your jars in the pressure cooker until the last last moment, then remove the lid from the PC and then from the SAB / GB and place them in there as quick as possible and close the lid and let them sit for 10 mins, allowing airborn contams to fall to the bottom.

Clean your hands and then put your clean hands in the SAB / gb and gently wipe the floor with the cloth so you clean the area, then let it sit again for about 10-15 mins.

Do all your work in your SAB / GB, so as soon as your jars are ready, put them in, wait, clean floor, wait, inoculate / inject with your spores / lc write the name of the strain and the date on them, then move them to an incubation chamber (IC).

The making of an IC is super easy, just two big plastic tubs inside each other with some bleach filled water in-between the tubs and a fish tank heater set at about 78-80f. Clean the inside with bleach, then peroxide then alcohol, using fresh paper towels each time.

Wait for it to colonise half way then shake them up, and wait for them to colonise fully, then as soon as they are ready, if you want to make more, do a grain to grain transfer in a SAB or GB and wait again, then when ready to spawn to bulk follow your normal method.

If you do it this way your spawn will grow at its fastest rate, there will be almost no issues with contams in your spawn, and when spawning to bulk, ideally pasteurised coir / hpoo you can just leave it at the right temp, again 78-80f and it will colonise the sub as fast as possible, faster than it takes for any contaminant to take hold.

Try to avoid using casing layers, that's where most contams come from, but you can have great success with them, it's your choice.

That way the issues you are having with contams will be greatly reduced and you should have much more success in your endeavours.

I hope I haven't bored you to death

I hope this helps somewhat.

Much love, inf <3

Having enough holes in the tub is key. I graduated to larger holes and plenty of them on all sides and the top. Another good trick once fruiting has been initiated is to only open the tops outside to fan.
I try to never open the tubs inside the house. This really makes a difference in minimizing the start of inevitable contamination.

A fully colonised tub is quite resistant to contaminants.

I have found that having no uncolonised hey / straw / coir / hpoo (What ever substrait you are using) left in the tub, on the walls, poking out from the sub etc, really helps prevent contams.

I find I get the best results with a flat and level substrate, I wipe of any spill from the side of the tub mess, I have no hay poking out from the sub, this, in my experience, allows the entire sub to get colonised and there is nothing left for contaminates to grab hold of.

In the end all substraits will contaminate, this is due to the mycelium getting weaker as it consumes all the available food and ages, then it is more vulnerable and trich can take hold.

I used to do a really mild bleach dunk between flushes to stave this off a bit, but it can be hit and miss and some mycelium may react negatively to the bleach and degrade quicker. Best bet is make super flat and super clean subs.

Good air flow when fruiting ensures fatter stems and thus more mushroom mass / weight giving you heavier shrooms.

But its important with airflow to ensure the humidity stays constant. When in the pinning stage air flow allows water to evaporate from the tub which is a huge pinning factor, but maintaining the rh in that stage is crucial. So if you have high air flow, ensure you either mist regularly or you have a humidifier in the room so the new fresh air entering the tub is moist and will not dry out your sub to much.

<3

There is a type of plastic film similar to parafilm but with higher gas exchange rates. Maybe use something like that?

Cant recall the name but its used a lot in bio labs.

You mean this stuff 3M™ Micropore™ Surgical Tape ?

3M™ Micropore™ Surgical Tape

For grain jars i drill a 1/4 inch hole and put either polyfill in the hole or use two or three layers of micropore tape. For tubs just use bigger holes maybe 2inch, six in total. One on each side at both the sub level and the top of the tub.

I used Tyvek for monotubs (cut to squares and attached with a duct tape) and Micropore tape for grain jars.

I however switched back to poly fill for both jars and monotubs (even for LC jars), since it's cheap and easy to replace.

Cotton wool or glass wool might also work but I haven't tried. Cotton absorbs moisture so it's not good as wet cotton will provide a vector for contams.

For grain jars I use a small square cut from old bluejeans and micropore tape together as a filter patch, the idea is the denim gives a larger gas exchange area on the tape and the tape wont get covered by a film of goo from shaking the grain. I reuse them several times before replacing. [Ignore the plastic tape over the inoculation hole, bad experiment]

For dubtub bottoms what I've been doing is to take a plastic food bag large enough to slide the tub into, I put on a piece of tape and then hole punch that and put on a piece of micropore. As you can see from the condensation, GE occurs. I've done half a dozen this way now and they colonize just fine. [Yes those are hybrids sharing that tub, F1's made with verified Transkei monokaryons ]