Substrate question and cycle

[Negseven]

Hi, couple of questions - just starting a 125 litre tank, can I wash some sand substrate and leave it in the tank (without water) for a while say 2 weeks without there being any problems (tank is under stairs, and is shady, temp is about 25) ?Also building on from that, could I setup the tank fully (adding live plants) turn on the filter and heater and get the cycle going, but after about 1 week turn off electric (going away for 4 days) and resume cycle when back. Would tank be okay to continue without any probs?

 

[Valkyrie_Lips]

It might be harder to get the sand to settle if it dries out and then you add water. You would probably end up with a cloudy tank. I would just set it up when you get back.

If you're going to get the cycle started you need an ammonia source, running the filter does nothing but aerate the water. Turning the filter off for 4 days will not kill any small amount of beneficial bacteria you grow in a week. I'm not sure how your plants would fair without the oxygenated water though.