And i water them with distilled water with a ph of about 6.5
It's still hard to tell what deficiency you have as both Nitrogen and Magnesium have very similar symptoms early on. Without more information, the only sure way to know by looking at the leaves is after the symptom progresses and the plant sheds its leaves.
Nitrogen deficient plants leaves go all yellow and then slightly darker amber yellow in places before going brown through stages of light tan to dark brown and then dropping off. Magnesium deficient plants tend to yellow between the veins and leaf ends before moving further up the leaf turning it yellow, but the centre of the leaf tends to remain green while the ends start turning and shrivelling up and going light brown to dark brown, you also get these dark brown rust coloured spots with Magnesium and they progress UP the plant to new leaf growth in advanced stages as well.
Now that you've mentioned you're using distilled water, it pretty much confirms in my mind that you have Magnesium deficiency. Repotting won't always help Mg deficient plants where it will Nitrogen deficient ones because there's not an awful lot of residual Magnesium in compost whereas there is Nitrogen. This is why experienced growers add dolomite lime and Calcified Seaweed to add back in Magnesium and Calcium to the compost and to help feed micro-nutrients to the soil micro fauna. Plants also get a good supply of micro nutrients and Magnesium and Calcium from tapwater and that's why using distilled water which has had all its dissolved salts removed, including Magnesium and Calcium can produce Magnesium deficient plants.
Magnesium also tends to reduce in availability in soil at low ph's of 5.5-6.0, so feeding a lowered ph irrigation water will start to move the compost ph downwards which isn't really what you want to do.
Compost is ph self buffering. What that means is, that compost comes with its own ph which can be anything between 6.5-7.0 and the only way you'll change that ph is by watering with a lower or higher ph water than the composts own ph value. The ph movement is also very slow and that's what we mean by 'ph buffering', in other words it's going to take an awful lot of water out of the composts own ph range to start moving it, and by the time that happens the plant is either repotted or harvested. This is why ph is rarely ever an issue in soil compost grows as long as you're dealing with decent quality ph adjusted compost and irrigation water that is within reasonable ranges of the composts ph value. The more out of range the water is the faster the ph movement will be. This is also the other reason experienced growers use dolomite lime in their composts - it helps and adds to the composts ph buffering ability and ensures the compost ph value can't go above 7.0. As many peoples tap water ph is 7.5 and above, dolomite lime can be very helpful in controlling the compost ph as well as adding Magnesium and Calcium.
My suggestion to you for your problem is to start feeding it 50/50 Distilled water and tap water and add in about a tablespoon of epsom salts per gallon of water. Dissolve the epsom salts first in some warm water. You can also foliar feed epsom salts at a slight reduced quantity of about 2-3 teaspoons per gallon. Unfortunately your damaged leaves won't improve and all you'll manage to do is stop the problem spreading or put it in check. You can also use something called Cal/Mag, but I have no experience of that myself.
You then need to find a solution to this for your next grow, which may just mean using 100% tap water, but it might be worth just checking on the EC and PH of your tapwater first.
Long post, but I hope this may help a few people with N, Mg and Ph problems.