Consider yourself lucky with well water of 5-10ppm nitrates as the nitrates in my well water is 80+ppm!
I went to a nearby town and their municipal water was 20ppm.
Now many hobbyists seem unconcerned with high nitrates. I have seen some claim that nitrates are not an issue unless they're 200ppm+. I have to disagree
. Although not as toxic as ammonia and nitrites, nitrates are toxic to fish long term. I lost many fish, especially young fish before I realized and understood my water problem. High nitrates stunt fish growth, lower immune systems and dramatically shorten the life spans of most fish. Any measurable nitrates are lethal to corals and many SW fish and although some FW fish may be more hardy than others and survive, high nitrates in aquariums is not healthy. We must also consider that in nature, nitrates are so low in FW they can barely be measured. All the more reason to get/keep them as low as possible in the aquarium.
As mentioned, with ample plants, careful feeding, good tank/filter maintenance and regular weekly water changes of 50% you should be able to keep nitrates under control. You might also consider a small gravel or sand substrate of about 3" or so which might encourage anaerobic bacteria that will convert nitrates into nitrogen.
I am experimenting with a DIY bio-denitrate filter (documented in the DIY section of this forum). It uses Seachem Matrix and De*Nitrate which simulates live rock used in SW). So far, however, although ammonia and nitrites are handled, I have yet to claim success processing nitrates with anaerobic bacteria. I'm still hopeful it will kick in.
In my case, I've used products like Fluval Lab Series Nitrate Remover (FNR) and API's Nitra-Zorb in the tank filter to lower tank nitrates. These are synthetic scavenger resins that adsorb nitrate and are rechargeable in salt water, making them resuseable. I am also periodically using activated carbon and Seachem Purigen (a synthetic resin that adsorbs dissolved organic compounds) along with some Anacharis
floating plants, careful feeding and good tank/filter maintenance to keep nitrates low.
For water changes, I bought an API Tap Water filter to create deionized (DI) water. DI water is too pure for aquarium fish so additives adjust for minerals and pH (I'm currently using Seachem Replenish and Seachem Neutral/Alkalinity Regulators). Since my yield of the filtered DI water is only about 50g per ($25) filter cartridge, I setup a spare 10g tank in my garage and use FNR to filter my well water. I use a 50/50 mix of the DI and FNR filtered water to produce a 10g weekly water change for my 60g tank and add a weekly dose of Seachem Fresh Trace (to ensure ample trace elements).
I've been doing this for about 3 months and so far the fish are healthy, active and no more fish loss. As mentioned, with ample plants, careful feeding, good maintenance and religious weekly water changes, you should be fine... but monitor nitrates to keep them as low as possible.