CO2 removal from mushroom growing tent I'm trying to grow oyster mushrooms that like high temperatures. They look great in an indoor terrarium, and can eventually yield several tasty meals :)

However oyster mushrooms are hard to grow indoors, because they need low $\ce{CO2}$ levels (&lt;1000 ppm according to Paul Stamets), AND high humidity (>95%).

Warm climate oysters tend to grow fast, and can generate quite a lot of $\ce{CO2}$ fast.

If I vent the air in tent about 10 times a day, humidity will suffer (and I can't do that all the time).

If I close the tent, mushrooms will be stunted and club-like, and yields will be next to nothing.

I'm thinking about putting a tray with $\ce{NaOH}$ crytals on it, probably with a fan to slightly move the humid air around a bit.

An other method would be to use an aquarium pump to bubble air through NaOH solution.

My questions are:


Does this look like something feasible? Can some $\ce{NaOH}$ remove enough $\ce{CO2}$ from the air to keep it under 1000ppm?
Which of the above methods seem to be the better one given the aquarium pump can bubble about 100-200 litres of air in every hour and the tent is about 500 L ?
Please stay away from sodium hydroxide, it's way too nasty to use in non-lab setup. You can handle it safely in dry conditions, but in contact with water, it becomes sticky and causes bad burns.

As a substitute, I suggest $\ce{Ca(OH)_2}$, readily available as slaked lime. You can structure it into relatively high-surface sculptures and it solidifies into common plaster upon binding enough $\ce{CO_2}$. It is often used for this purpose due to its low price, low toxicity and ease of handling.

In your situation, I would just put some vertically fixed mesh soaked in very viscous suspension of calcium hydroxide. In the high humidity conditions you'd have no problems with normal drying, so once it solidifies it has done its job and you can just hit the mesh against the ground to crumble the plaster away and put on new layer. It is advisable to use gloves and goggles, but it is not as necessary as it would be in the case of sodium hydroxide (look at all the masons around).