Trouble shooting guide – AquaFX The AquaFX Stingray User Manual
Page 8

Trouble shooting guide
Problem
Solution
High TDS after
membrane
Clogged Pre-filters. Causing Pressure Drop. Insufficient pressure will yield 
poor TDS rejection from RO membranes. Change Pre-Filters. 
Average Membrane life is 2 to 3 years. Most common cause for 
membrane failure is insufficient pre-filter maintenance. AquaFX Carbons 
are rated for 3,750 gal @ 1.0 GPM of 2ppm Chlorine. Do not exclude 
drain water from this capacity, as it is treated water. Very high TDS 
(>550ppm) may also yield premature failure.
Low incoming water
pressure.
Incoming water pressure must be above 40 PSI, Add a booster pump if 
below 40psig. Make sure Pre-Filters are not clogged causing low 
pressure.
No water to drain.
Flow Restrictor is clogged, Replace Drain Flow Restrictor. (rare) 
Check to see if water is turned on.
All water is going
out of the drain
With no back pressure, most of the water will exit out of the drain. Make 
sure a Flow restrictor is present. 
Very little/slow
water production
Reference units flow rate vs. actual production. Slow flow from RO is 
normal. Cold water, low pressure and high contaminant levels will 
contribute to decreasing the rate of water production. Heating water (NO 
WARMER THEN 80 Degrees F), increasing pressure or additional pre-
filtration will help to counteract these adverse affects.
Drain Water
Continues After 
Product line is full
The most common cause of a ‘continuing drain’ is a pressure leak on the 
product side of the RO. If the pressure cannot build, the automatic shut-off 
(ASO) will not close. Check ASO with a ball valve right after RO. Close 
Ball valve then wait 1-3 minutes. If drain continues, replace ASO Valve. If 
it stops, have the customer, find then stop pressure leak. If a float valve is 
being used, it is more than likely the culprit.
The incoming feed
water TDS has 
increased.
An increase in feed water TDS will also give an increase in Product Water 
TDS. R.O. (Dolphin) Users will see this rise in TDS, due to the membrane 
removes a percentage of TDS. 
RO/DI (Barracuda, Mako, Great White) Users will not see this rise, but the 
DI will exhaust faster than normal.
DI is
exhausting 
very fast 
R.O. Membranes are manufactured with a preservative on them, if your initial 
startup allows the membrane to ‘rinse’ into the DI; there will be some immediate 
exhaustion, followed by normal exhaustion. 
 
Chloramines Vs Chlorine 
– If the customer’s water is disinfected with
Chloramines (NH
2
CL) the ammonia portion will still be present post RO.
 
For R.O. (Dolphin) users, they may wish to purchase DI to remove the 
ammonia.. 
 
RO/DI (Barracuda, Mako, and Great White) users will have the ammonia 
removed by the DI. This will tax the DI, Chloramines appears in several 
forms, so the decreased life would depend on the state of Chloramines. 
(mono, di or tri) 
