Clone getting worse

I posted here a few days ago about yellow/brown tips. I was told she needed some nutes, which I did but it has since gotten worse.
My ph meter needs calibration and the hydro store had no buffer solution. Could it be ph? nute lock out? or should I continue with just water?
I don't think heat is an issue as it's under low watt cfls for now.
I have no idea what to do. Help please and thank you.

nitrogen deficiency. Sorry it's very late and i'm heading to bed so i just posted all the info you should read about to make sure it's correctly diagnosed. at the bottom is a list of nutrients with the proper N needed to correct the problem
https://www.rollitup.org/nutrients/712483-nutrient-pest-prolem-solver-pictorial.html

Nitrogen Deficiency

Cannabis is a fast growing plant species and requires generous amounts of nitrogen throughout growth and early flowering. Nitrogen is regarded as belonging to the group of three primary nutrients essential for plant growth. The other two nutrients in this group are phosphorus and potassium. These will be dealt with here separately. Nitrogen is stored mainly in the leaves and shoot tips, which is why it is inadvisable to remove healthy leaves on plants, as these are the "storage house" for important nutrients. The production of enzymes, proteins, chlorophyll and other vital ingredients for healthy development are all dependent on nitrogen. Chlorophyll lends plants their green color which is why yellowing leaves are a telltale sign of N deficiency.
Causes:
A serious pest infestation of aphids, white flies, or spider mites that suck out the leaves leads to deficiency symptoms.
Too small container size for adult plants is one of the most common mistakes in cannabis growing. Especially in light intensive situations such as balcony or garden grows the plants will quickly yellow and wilt. Don't be too lazy and repot your plants. You can do this up to the third week of flowering even.
Poor soil quality. The second major cause for a deficiency. The importance of using quality grade horticultural soil cannot be stressed enough. Do not use topsoil from the forest if you are not certain about it's nitrogen content. Decomposed leaf material contains no nitrogen (obviously since these are the yellowed leaves shed by the trees!) and makes up for a large percentage of forest topsoil. Also loamy and sandy soil are mainly devoid of important nutrients. If you do utilize such soil in guerilla grows, etc. then make sure to supplement it with long term acting fertilizer, or enrich it with a mix of organic nutrients (bat guano, composted soil, etc.) that have sufficient quantities of nitrogen to support plant growth.
A pH imbalance will block nutrient uptake in the root zone. Make sure that you keep the pH within the acceptable range for soil or hydroponics.
Lack of fertilizing. A minimum of fertilizing on soil is usually necessary to boost plant growth, since cannabis tends to grow faster than the roots can assimilate the natural nutrients in soil. In low light situations or indoors this is less of an issue than in a greenhouse/outdoors/or in a setup using CO2. With high quality soil and a good container size you can probably do without any grow fertilizer if you are cultivating short to medium sized plants.
Symptoms:
The lower leaves yellow between the veins until the entire leaf is eventually yellow. It wilts and dies.
The symptoms spread upwards affecting all sun leaves and then the smaller and younger leaves as well.
Plant growth is inhibited. The plants remain short and underdeveloped if nitrogen deficiency is severe in the growth phase.
During flowering early deficiency can lead to a significant decrease in yield. Plants that are in the last 3 weeks of flowering do not require nitrogen if they have remained reasonably healthy up to that point. A yellowing and shedding of leaves during the final weeks of flowering is quite natural among otherwise healthy plants and should not be held up by heroic dosages of nitrogen (which would result in many undesirable complications such as: mold, sudden stop in bud development, dying of pistils, over-fertilization, rejuvenation/leaf growth in buds).
Appearance of male flowers on female plants.

Click to expand...

Solution to fixing a Nitrogen deficiency

Avoid excessive ammonium nitrogen, which can interfere with other nutrients. Too much N delays flowering. Plants should be allowed to become N-deficient late in flowering for best flavour.
A goof solid N-P-K ratio will fix any nitrogen deficiency. Any chemical or organic fertilizers that have Nitrogen in them will fix a nitrogen deficiency., Peters all purpose plant food 20-20-20 is good, Miracle grow All purpose plant food, Miracle grow Tomato plant food, (Only mixing at ½ strength when using chemical nutrients, or it will cause nutrient burn!) as well and blood meal! If you need to give your plants a quick solution to nitrogen and you want to use blood meal, I suggest making it into a tea for faster use, where blood meal is slow acting, but when made into a tea it works quicker! Other sources of nitrogen are dried blood, Cotton seed meal which is slow acting, Insect eating bat guano which is fast acting. Bone meal which is a gradual absorption when not made into a tea.( also excellent source of phosphorus). Fish Meal Or Fish Emulsion is a good source of nitrogen and is medium acting. Worm castings, which is gradual absorption. Seabird guano, All purpose Millennia Seabird guano, Original Seabird guano All Purpose, Crabshell ,which is slow absorption. Fox Farm Grow Big, which is fast acting. ( can bring down your pH as well)
Here are a list of things that help fix a Nitrogen Deficiency:

Chemical Nutrients

Advanced nutrients Grow (2-1-6)
Vita Grow (4-0-0),
BC Grow(1.2-3.2-6.5)
GH Flora Grow (2-1-6)
GH Maxi grow (10-5-14)
GH floraNova grow (7-4-10),
Dyna gro Grow (7-9-5)

Organic Nutrients

Dr. Hornby's Iguana Juice Grow (3-1-3)
Advanced Nutrients Mother Earth Grow (1.5-.75-1.5)
Earthjuice Grow (2-1-1),
Pure Blend Pro (3-1.5-4)
Bone Meal(0-10-0)
Blood Meal(12-0-0)
Fish Emulsion (5-1-1)
Seabird Guano (11-13-3)
Crab Shells(2.5-3.0-.5)
Pure Blend Grow (0.4-.01-.5)
Marine Cuisine (10-7-7)
MaxiCrop Seaweed (1-0-3)
Super Tea (5-5-1)
Mexican Bat Guano (10-2-0)
Sea Island Jamaican Bat Guano (1-10-0)
Kelp Meal (1-0-2)
Seaweed Plus Iron
Neptune's Harvest (2-4-0.5)
Alaska Start-Up(2-1-2)
Bio-Grow (1.8-0.1-6.6)
Age old Grow (12-6-6)
AGE Old Kelp (.30-.25-.15)
Neptune's Harvest (2-4-1)
Maxicrop Seweed(.1-0-1)
METANATURALS Organic grow (3-3-3)
METANATURALS Organic nitrogen (16-0-0)

So adding anyone of these above should fix up your nitrogen deficiency! Nitrogen deficient plants usually recover in about a week, affected leaves will not recover.

Now if you added to much chemical nutrients and or organics, (which is hard to burn your plants when using organics) you need to flush the soil with plain water. You need to use 2 times as much water as the size of the pot, for example: If you have a 5 gallon pot and need to flush it, you need to use 10 gallons of water to rinse out the soil good enough to get rid of excessive nutrients. Soluble nitrogen (especially nitrate) is the form that's the most quickly available to the roots, while insoluble N (like urea) first needs to be broken down by microbes in the soil before the roots can absorb it.


Note: Blood Meal, Dried Blood, Guanos, Kelp Meal, Cotton Seed Meal, Peat Moss, Sulfur and fish meal are all acidic and can bring your pH down, so if you add these please monitor your pH when using those.

Note: Bone Meal, Rock Phosphate, Wood Ashes pretty much all ashes, Shellfish Compost and Crab Meal are all alkaline and can make your pH go up, so if you add any of these please monitor your pH.

The mother plant was sick and now the clone is struggling to recover.