Help choosing an RO system in Sweden

I’m looking for an RO system to handle high potassium levels (K = 94 mg/L) and fluoride (F = 2.1 mg/L) in my water. The manganese (Mn = 0.30) and hardness (9.2 dH) will be addressed with a water softener using a Crystal Right medium.

In Sweden, the cold climate keeps groundwater temperatures around 5–7°C (41–45°F), which I’ve read can cut membrane output by about half (2.5–3% per °C, so an 18°C difference means roughly 54% less) compared to its rated performance at 25°C. This means a 75 GPD pump-less unit would produce only about 5.44 l/h (1.44 GPH) or less at 7°C, which feels far too little for my comfort.

I think I want a high-output system, ideally around 1 L/min, with my largest use being (I think) about 6 liters for a humidifier. My waterpump (drilled well 70m) will be set to 3-5bar (43-73 psi) at pressure tank(maybe 5-7psi lower at RO-system due to 3,5m(11,5ft) heightdifference and pipes), If needed I can raise this a little more (0,5bar/7psi).

Because of cold water, low pressure, and not wanting to wait 2 hrs for 10 liters, I’m considering an open-frame 400 GPD setup with a pressure pump and a 3–4 gallon tank (to combat , using 10" filters for cheaper replacements instead of expensive proprietary ones.

Since home RO systems are very rare here due to generally excellent water quality, local options are limited, so I’ll likely have to order from amazon.se with even there very low options.

For those with more experience, what would you recommend? What are the pros and cons, and is the pump noisy under the sink?

As a handy electrician, I prefer investing in high-quality items over cheap pumps and filters. I need two systems—one for the house and one for the shop—that can provide water for both the kitchenette used by two employees and the automatic coffee maker, making strong water flow essential when brewing multiple cups at once.

So far, I’ve come across these options:

1. Naturewater NW-RO400-B3LS3 (320 USD)
   Naturewater 5-stage Filter system 1500l/day Osmosis Reverse
2. A “cheap” Chinese 800 GPD model (500 USD) – Vattenfiltersystem 800 Gpd nivå 5 filtrering RO omvänd osmos system filtersystem, akvarium 3013-800G vattenrenare : Amazon.se: Home & Kitchen

What are your thoughts on these RO systems?