Phal leaf retention and Yellowing leaves

[YokaYampi]

Hello!
My orchid collection like many others started with phals, i grow them under LED lights on a shelf in my bedroom. That is until the orchid bug bit me a littler harder and i got a small 2x4x5 grow tent. It's fully operational with Wifi timers and triggers for temp, humidity and light.
The issue im having is that i cant seem to retain a large number of leaves on some of my orchids. They grow, they bloom but they arent gaining leaves. They'll loose for every one they grow. instead of growing lets say 2 and loosing 1, this is making it so theres no retention of leaves.
A Tetraspis C1 started getting lighter color on the edges of the leaves so i thought it might be a magnesium deficiency. So i gave it a little magnesium.
The other orchid im worried about if the Tetraspis x livida who's has very nice green leaves up until a little bit ago where the hue has turned from that nice deeper green so a lighter yellowy color

i normally fertilize weakly weekly with an msu
Could it be too much light? not enough light? or a virus maybe?
here are pictures of both orchids


honestly this issue is really frustrating, any insight would be wonderful!

[estación seca]

Photos didn't come through. Light color in warm-growing Phals often means high light. They don't do better with more than they need. Poor leaf retention may be caused by high light, low humidity, low temperatures, inadequate water or roots unable to take up water. Spider mite damage under the leaf can look like yellowing above the leaf. Tetraspis and livida do better with higher temperatures and humidity than the big round-flowered Phals.

What are your temperatures, humidity, and light? What is your potting medium? How are you watering? Look here in the Pests forum and read about spider mites.

[YokaYampi]

Originally Posted by estación seca

Photos didn't come through. Light color in warm-growing Phals often means high light. They don't do better with more than they need. Poor leaf retention may be caused by high light, low humidity, low temperatures, inadequate water or roots unable to take up water. Spider mite damage under the leaf can look like yellowing above the leaf. Tetraspis and livida do better with higher temperatures and humidity than the big round-flowered Phals.

What are your temperatures, humidity, and light? What is your potting medium? How are you watering? Look here in the Pests forum and read about spider mites.

oh no! hows this?
Imgur: The magic of the Internet


I have a feeling it might be too much light. in the begining of growing i made the mistake of confusing light with love and giving them a lot aha
I used to do 14 hrs and reduced it to 12hr however ive been having a sneaking suspicion that even that was too much. The shelf i my room unfortunatly doesnt get as much humidity as i would like, maybe 40% - 55% the tent on the other hand gets 75%-80% with a low of 17c at night and high of 25c in the day ( this is the winter temps as in the summer it warms up)
Ive known the low humidity is an issue so i moved them to the tent, which also has higher temps as well.
since im in canada the room temps are around 19c-21c during the winter
as far as mite damage, i bought a microscope a while ago and have been checking the orchids, no spider mites but ill do another inspection just in case, thank you for the reply!
As far as calculating the amount of light vs the lux ( i have a light meter) and how long to keep the lights on do you have any tips?
If the recommendation is lets say 12000lux would that be for 8 hrs?
could i reduce the light intensity and increase the exposure?

[Ray]

Originally Posted by YokaYampi

i normally fertilize weakly weekly with an msu

Welcome to the Orchid Board!

Can you please put some numbers to that phrase?

Which MSU fertilizer 19% or 15% N?

How many ml/L or tsp/gal?

When you water, do you flood the pot or just trickle some solution in?

[YokaYampi]

Originally Posted by Ray

Welcome to the Orchid Board!

Can you please put some numbers to that phrase?

Which MSU fertilizer 19% or 15% N?

How many ml/L or tsp/gal?

When you water, do you flood the pot or just trickle some solution in?

K -lite ( for total specs) K-Lite Orchid and Epiphyte Fertilizer › First Rays LLC
1/2 Tsp weekly in a 4 l/ 1g distilled water
The N is 12.95%

[estación seca]

That should be adequate nitrogen and most minerals. Magnesium deficiency can take a long time to replenish. I think the low leaf count is due to a combination of low humidity and low temperature. This kind of Phal tolerates 17C at night but it would be much happier in the 20-35C range. They prefer a hot and humid climate.

[YokaYampi]

Originally Posted by estación seca

That should be adequate nitrogen and most minerals. Magnesium deficiency can take a long time to replenish. I think the low leaf count is due to a combination of low humidity and low temperature. This kind of Phal tolerates 17C at night but it would be much happier in the 20-35C range. They prefer a hot and humid climate.

Thank you for taking the time to help me, I’ll keep it in the tent that’s far warmer and reserve my shelf for the intermediate low temp tolerating orchids