I've read several threads where people are saying that Kh < 1 isn't a problem if your pH is fine.
I would like to know what I can do...
Should I just keep doing water changes untill my nitrates are restored to healthy levels?
How do I avoid this type of nitrate spike in the future?
Idk if this is going to make sense or not, but I will try to provide some info.
1) Kh @ <1
- Could have some negative impact on the stability of your pH, especially in a low tech tank without c02. With a next to nil Kh in a low tech tank, it's almost certain that if you test your ph, it will drop when the plants expire c02 at night, maybe even drastically, maybe your ph is
very low. At a ph of 6.0, your nitrification process would stop. This could allow for the spike in ammonia, just a guess, but it would be good to figure out why your ammonia spiked in the first place. Sure, a bunch of dead shrimp will increase the ammonia, but why did the plague start, I don't really think one dead shrimp out of the blue would be too much for the BB to handle.
2) GH and KH go hand and hand to control the PH, but it's carbonates that play the bigger role in stability. For a shrimp tank, your ph should be at least slightly on the alkaline side to maintain their shells. A kh of 2, preferably 3 would give you slack and keep your ph more stable, imo.
3) I have found that plants use Kh when c02 is not available (already used up by the plants) as a source of carbonate, and when your KH is consumed by the plant cycle (expire o2 during the day and co2 at night), you will lose your buffering capacity and possibly put your aquarium inhabitants at risk of damaging ph swings.
I know this info is all over the place, but hopefully it makes a bit of sense to give you an idea of what could have happened and how to prevent it later. And I would do frequent w/cs until your nitrates are much lower, this will hopefully replenish kh at the same time (source from your tap water), very little of the BB is stored in the water column, and in a well balanced, low bioload, planted aquarium, your N03 should be <5ppm, possibly even 0ppm. 0ppm is the case with my tanks, although this is not ideal for plants, (they are using up the nitrates too fast as fertilizer) I still have a lot to learn, but when your inhabitants are dying, it's important to at least address that first, imo. Good luck.