I have a plan for a 1000 gal pond. I would like to add a skimmer but have some concerns:

Is it best to get the type of skimmer that can house your pump? And wouldn't this limit your options to add a pre-filter?

Do I have to cut into the liner for this? I know there are types that don't require that but are they effective or just novelty items?

As the skimmers are fairly large, isn't it difficult to hide?

I've never bought or had a skimmer but will tell you what I think.

I agree that having the pump in the skimmer does limit your pre-filtering abilities. Normally, there's a mesh bag or maybe some filter material in the skimmer right before the pump but it sometimes may not be enough. I don't see a problem with having an out-of-water (in-line) pump outside of the skimmer box. Our pool goes from skimmer down pipes to the diatomaceous earth filter and then to the pump and finally back to the pool. The filter thus in that case fills by gravity with the pump pushing the water back out to the pool.

I think you do have to cut the liner to put in a real skimmer. I've seen little skimmers that sit in the pond itself and pull water from the surface. They are very small as far as water turnover and have very little pre-filters or filtration.

I don't think the skimmers are too hard to hide because they are buried in the ground next to the pond. Theoretically, you can cover them with whatever you want - fake rock, fake grass, mulch or rocks glued on a board, potted plants, etc. I would just avoid things that are heavy.