Can someone help my amnesia lemon out?

A little background...

Light: 90w UFO
Distance: approx. 4" above the plant
Medium: 60% MG Potting Soil, 20% Peat, 15% Perlite, 5% Sand
Age: 25 days above ground
Water: Distilled
Soil pH: Unknown, i don't have a soil tester yet
Nutes: None yet

Concerns:
1. It's a really dark green color.
2. The growth is filling in underneath but its not growing up.
3. Yellow spots starting to form on the leaf edges.
4. New shoots are yellow/pale green compared to the rest of the plant.

Ok, here is my diagnosis but i would like others opinions before i try anything and make it worse.

Is my light too close causing it to bush up but not grow up?
Since i'm using distilled water is my plant not getting the smaller nutrients it needs to grow??

I tried to look at some of the sticky guides but the pictures wouldn't load for me making it harder to diagnosis what nutrient was actually deficient or toxic in this case. If somebody could tell me what i'm doing wrong and what i could do to make it better it' be much appreciated and you will receive +rep in return.

In the first picture you can see yellow/rust looking spot
In the second you can see the the overall growth, and that dreaded spot again
In the third you can see the pale green looking shoots
In all notice how dark green looking it is

It's hard to say much with the purple pics but it looks like the Ph may be too high.

I don't have any pH down and the nearest grow shop is over 2 hours away. I think read somewhere you can use vinegar to bring it down?? If so how much and do I mix it with the watering or do I add it straight to the soil?

Can anyone tell me why the Tip of the main Cola is Pure white except with a few little red hairs peaking out? It's 3 weeks into Flower. Is it bleaching from the light being to close? Or a Nute Def?

Sorry for missing the previous post. Imo all growers should have a soil Ph tester and a liquid Ph test kit. You need to check the soil's Ph before making corrections. We use lemon juice to lower Ph but Vinegar works also. The lemon juice supplies extra Vitamin C which is necessary for plant growth. A liquid test kit can be had for 5-10$ and with it you will be able to tell how much acidifier to add. A capsule-type soil test kit can be found for as much or less. I usually reccomend getting a liquid test kit, a capsule-type soil test kit and a probe-type soil tester. Use the probe on the soil and use the capsules once in awhile to make sure the probe is still reading correctly. Altogether they should cost 30-40$.

Test the soil Ph immediately if you haven't yet. Check the temps at canopy level and post what you're feeding it. It really looks like it needs Phosphorus asap, not that this is the only problem.

Some strong sources of P are Bone Meal and most Guanos.

You are getting curling fan leaves towards the main stalk indicating an overfeeding of nutrients as well as the new growth being a "witches broom". This is also caused by the Ph being off.

hi mate, the cola on the plant is pure white because your LED was too close and bleached it, too late i know but may help you for next time