Unhelpful Axolotl

[Lil RED]

So my nitrates are sort of high right now (70ppm) and I'm getting them down asap ofc but I had no idea because my Axolotl is showing no absolutely 0 signs of stress! (He's not overly active or inactive is eating great I just bed him 4 brine shrimp cubes and his gills and tail are not curled at all) and I'm just confused on why that is?! I also just cleaned the tank today (55% changed for a 20 gal)

 

[wolfen]

nitrates although bad aren't as toxic as the other two nitrogen compounds (ammonia, nitrites), axolotls can tolerate high levels of nitrates before having any effect which is easier to spot with white/albino axolotls then wild/mel axolotls, high nitrates affect axolotls the same way as nitrites which is by poisoning the blood and inhibiting the bloods ability to hold oxygen, this causes a condition called brown blood (which is more noticeable with white/albinos due to their semi translucent skin) other symptoms are lethargy and lack of appetite.
axolotls can tolerate up to 110ppm of nitrates which is 55x higher than ammonia (2ppm) and 220x higher than nitrites (0.5ppm) although not very pleasant though.
if an axolotl is suspected of nitrite/nitrate poisoning methyline blue baths can be used to reverse the effects and help oxygenate the blood.
50% holtfreters solution can be used in the animals habitat (aquarium) to help protect against high levels of nitrogen compounds as well as making the water more suitable for axolotls.