Long ago I used to grow under lights but things have changed since then. If I were trying to figure this out for myself I would probably look at PPFD for whatever lights you're buying (assuming that they are available and true - were at the mercy of the vendor to a certain extent). This will tell you the amount of light given off within the PAR area of the spectrum (the main part of the spectrum that plants use). See here for a good explanation - https://www.gardenmyths.com/led-grow-li ... -spectrum/. You also need to look at what portion of the PAR wavelengths suit your purpose - It sounds like you are just using these to get the seedlings going and if that's the case you should look for information on this. If you're trying to get plants to flower or do the full growth bit, then you might need something different.

Here's some information on the plant wavelengths you need (looks like 430 to 450 nm for seedlings based on this - https://homeguides.sfgate.com/plant-lig ... 72801.html)

As far as the water. You can use the aquarium water but for starting the seedlings initially, just plain old tap water may be better. The seeds generally don't need any nutrients as they sprout but as you move them on they will.

Cheers and hope this helps .