More testing the next day late afternoon (previous samples were also late afternoon).

Soluble Iron zero

Total Iron also looks like zero

BYPASS softener

Soluble Iron zero

Total Iron about .1ppm.

BYPASS softener, centaur carbon, and second Katalox Light tank

Soluble Iron 7-9ppm

Total Iron not tested

BYPASS softener, centaur carbon, and both Katalox Light tanks

Soluble Iron 9-10ppm

Total Iron not tested

Notes:

Total system is under ideal conditions resulting in no measurable iron
Softener isn't removing much iron

Second Katalox Light tank with Centaur Carbon tank are removing a great deal of iron.

Even with chlorine injection/retention time, calcite tank, and one Katalox Light tank 7-9ppm of iron remain in water.

I would have expected half that number or even less. Is the first Katalox Light tank doing its job?

The second Katalox Light tank and Centaur Carbon tank then remove almost all of that amount with softener doing a small amount of polishing.

As ditto suggested I should: "Backwash the KL tank and see how much iron is coming out during the backwash cycle. Once the water runs clear you should add several minutes after that in the backwash cycle. Be sure to have an adequate rapid rinse cycle."

I should also test the backwash of the softener. If the softener backwash contains iron then the toilet reservoir tank problem could be due to insufficient backwash time and/or use during regeneration?

Below you first see the total iron test of water out of the softener.

Second is the total iron test of water bypassing the softener.

Third is soluble iron test of water bypassing KL2 and Carbon tanks (this result was virtually indistinguishable from the test after bypassing both KL tanks).\

Iron CHEMets Kit results, mid afternoon
Soluble Iron zero
Total Iron .1ppm, maybe, see image below.
The first is using the soluble/ferrous iron procedure.

Regeneration times

Calcite 11:00 PM
20min
K1 11:30 PM
90min
K2 1:10 AM
90min
Carbon 2:50 AM
20min
Resin 3:20 AM
116min

11 to 11:20
11:30 to 1:00
1:10 to 2:40
2:50 to 3:10
3:20 to 5:20

All tank programming (use and master) and diagnostics

Kat one
DO
FR00
PF 10.9
HR 61
VU 891
RC 120
TV 115.7
SV 3.2
UP
DO 3
RT 11:30PM
H 20
SF 10
MP
DF Gal
VT 5810
RF df 2b
CT Fd
C 24.0x1000
H 20
RS SF
SF 10
DO 3
RT 11:30PM
B1 10
BD 60
B2 5
RR 10
BF 5
FM t1.2
RE OFF
VR OFF

Calcite
Diagnostic
FR 00
PF 2.9
HR 13
VU 116
RC 120
SV 2.4
User
DO 3
RT 11:00 PM
H 20
Master
DF Gal
VT dF2b
CT Fd
C 24x1000
H 20
RS SF
SF 10
DO 3
RT 11:00 PM
B1 10
B2 0
RR 10
BF OFF
FM t1.2

Kat 2 (third)
DO
FR 0.0
PF 9.4
HR 60
VU 553
RC 123
SV 2.4
User
DO 3
RT 1:10
H 20
Master
DF Gal
VT dF2b
CT Fd
C 24x1000
H 20
RS SF
SF 10
DO 3
RT 1:10
B1 10
BD 60
B2 5
RR 10
BF 5
FM t1.2

Carbon (fourth)
DO
HR 11
SV 2.4
User
DO 2
RT 2:50
Master
DF Gal
VT Fltr
CT tc
DO 2
RT 2:50
BW 10
RR 10

Resin (fifth)
DO
FR 0.0
PF 3.2
HR 40
VU 179
RC 317
SV 2.4
User
DO 3
RT 3:20
H 20
Master
DF Gal
VT dF2b
CT Fd
C 31x1000
H 20
RS SF
SF 20
DO 3
RT 3:20
B1 10
BD 60
B2 5
RR 10
BF 21
FM t1.2

Replaced RESIN and CALCITE.
Iron problems continued as detected via toilet reservoirs.
Noted a surge of iron on first opening J bath spigot.
Could this be a regeneration issue? Otherwise water appears good.
Replaced fine mesh resin. Valve appeared very clean.
Cleaned and replaced calcite. Valve appeared iron coated, but otherwise normal.
PotPerm and salt being utilized normally.
Will check programming information and valve cycling.

notes

Prompted resin regeneration for last night, Saturday night, with tank having 750g or so remaining. Today water looks good and no detectable iron in J's reservoir. Could be resin is now clean. Could be that when all valves are set to regenerate that they step on each others scheduling or that just the resin valve gets stepped on. Should review all regeneration clock settings.

Water mixed.
As of 2/2/19 water looks good and J's toilet reservoir has no signs of iron accumulation around Clorox tablet. Will next scheduled resin regeneration result in continued clean water or will it leave water with iron residue? This regeneration should occur around 2/4/19 or so, say Monday or Tuesday. So, I'll be checking every day, but by next weekend I should have a decision/results 2/9/19.
If a problem resurfaces should replace resin, clean valve, and review status of check valves. If it looks like trouble early I'll order resin right away. Should it be fine or regular mesh?