@leena, Great pictures!! Many thanks to @kelemvor for posting the How-To video!!

A couple of points to keep in mind if/when you get your new equipment -

1. Not sure what the purpose of that shutoff valve is right at the filter inlet but it seems redundant to me. Why do you have a shutoff there? If it is not necessary then do not install one on the new filter. I understand having one near the skimmer.

2. Re-plumb your pool, pump & filter connections with straight wall PVC piping, it is much better than flex-tube. Use schedule-40 PVC piping, joints and quick-connect unions where needed.

3. Plumb the new sand filter with PVC quick-connect unions to make it easier to disassemble and remove the multiport valve on the top of the filter. Add shut-off valves as-needed to keep the pool water from draining. Being able to easily remove the top of the filter helps when you want to do a deep-cleaning of the sand and inspection of filter internals. That kind of maintenance should be performed annually at the start or close of the pool season.

4. Not sure how much of a project you want to make this, but having your pool return located so closely to the skimmer means that the pool water flow is going to have lots of stagnant spots. I would think adding a second return to the other end of the pool (if it can be done easily and without much of an eye-soar) would be really helpful it keeping more of your water moving. Of course, an additional return run with a long stretch of PVC could possibly require a higher HP model pump, so it would be a big consideration.

Just thoughts, for whatever they are worth....