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Chemtrol 250 pH and ORP Digital Controller
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A Simple and Affordable Controller for:

Large Residential Pools and Small Commercial Pools
, Motels
Health Clubs
Apartment Buildings
Condo Associations
Municipal Pools


Part #





Chemtrol 250 Digital ORP and PH Controller



The Chemtrol 250 monitors and controls the Chlorine & pH Level in your swimming pool.   Designed for Commercial or Residential use.

Imagine a Thermostat on the wall that monitors and controls the amount of heat or cool air in your home.  In a similar respect, this is what an automatic chemical controller is. 
Water passes the probes that are inserted in the pvc lines of the pool filter system. 

When the controller determines when the pool needs more chlorine (which is determined by your "adjustable setpoint", it sends an electronic signal to the chlorine pump. 

The same is true for when the controller determines that the pH level needs to change.  The controller sends a signal to the chemical feeder for it to turn on.

This is a slow and continuous monitoring (and controlling) of the pool water.  It takes the guess work out of water testing and the guesswork of adding chemicals.

  • Controls ORP and pH,  Very Easy to Operate

  • Easy to Read Screen

  • Waterproof Cabinet

  • Proportional Feed – Means the units will gradually increase chlorine and/or pH as needed, until it reaches those “Set Points”.

  • Set Points are Adjustable.

  • Equipped with Safety Overfeed Timers – Means that it doesn’t overshoot the Set Point that you program.

  • 5-Year Electronics Warranty

The Chemtrol 250 is Affordable and Cost-Effective.  No more "... The lifeguard left the chlorinator on overnight" statements.  The Chemtrol 250 is user-friendly, easy to operate, and is ideal for high-end residential pools, small commercial pools, & light industrial applications.  We Believe in this product and support it fully! 


  • Easy to install
  • Simple to use
  • All Control Functions on Front Panel
  • Waterproof Cabinet with Clear Window Cover
  • Separate Adjustable Setpoints
  • Separate Adjustable Alarms
  • Acid/Base Selector
  • Proportional Feed with Adjustable Bandwidth
  • Separate Adjustable Overfeed Safety Timers
  • 5-year Electronics Warranty

Savings continue to accrue from the more efficient use of chemicals, avoiding over- and underfeeding, and from lower labor costs for water testing and repairs of damaged equipment. In particular, commercial operators save on specialty chemicals, customer complaints and health department shutdowns.

Easy to Install

Installation of the CHEMTROL 250 is as easy as 1-2-3.

  1. CONTROLLER - Connect the controller to the 110 or 230V output of the Timer in parallel to the recirculation pump.  This will prevent accidental feeding of chemicals when the pump is not running. Make sure to follow the electrical code.
  2. SENSORS - Install the ORP and pH sensors on the recirculation line or on the optional bypass line.  The two sensors can be mounted directly on the main recirculation line with 2" PVC tees, as shown on the schematic.  For recirculation lines over 2" in diameter lines, the sensors should be mounted on a 1/2" bypass line.
  3. CHEMICAL FEEDERS - Connect the chemical feeders to the 110 or 230V controller outputs, according to the manufacturer's instructions, making sure to inject the chemicals downstream of the sensors.  For a bromine or chlorine erosion feeder, install a corrosion-resistant solenoid valve on the intake line of the feeder.  The controller is compatible with most ozonators and electrolytic generators.

Easy to Operate

The CHEMTROL 250 ORP/pH Digital Controller automatically maintains both sanitizer ORP (oxidation-reduction potential or Redox) and water pH in pools and spas.

All operating functions are clearly labeled and accessible from the front panel, with Many Safety and Easy-Reset Features.

  • pH calibration from 4 to 10,
  • ORP setpoint from 400 to 900 mV,
  • pH setpoint from 4 to 10,
  • ORP and pH feed modes: off, manual, automatic,
  • ORP and pH proportional control bandwidth from 0 to 100% of the setpoint,
  • ORP high and low alarms from 400 to 900 mV,
  • pH high and low alarms from 4 to 10,
  • ORP overfeed safety timer from 0 to 999 minutes,
  • pH overfeed safety timer from 0 to 99 minutes.

To select a function, simply press ORP or pH and then the desired function.  The display shows the current function value.  Use the UP or DOWN arrows to adjust to the desired value.

Control Set Points

The standard factory-set ORP control level is 700 mV, based on the World Health Organization (WHO) and National pool & Spa Institute (NSPI) values for prevention of germs and bacteria.

PH:  The standard factory-set pH control level is 7.5. 

Below a 7.4 pH reading, the water causes eye irritation and corrosion of equipment.

Above a 7.6 pH reading, it also causes eye irritation plus water cloudiness, scaling, stains and reduced sanitizer efficiency.

To change the control levels, the operator presses ORP or pH and then SETPOINT. Use the UP or DOWN arrows to adjust the ORP and pH set points. To save the new setpoint value and exit, press SETPOINT again.

The controller then automatically activates the chemical feeders for sanitizer and acid (or soda) feed, as required to maintain the set ORP and pH levels - regardless of fluctuations in bather load, contamination and weather.  Like a thermostat maintaining a constant temperature, it prevents overfeeding or underfeeding, both of which are detrimental to good water quality.


When there is an alarm condition, the corresponding display flashes the alarm value:

  • ORP out-of-range,
  • pH out-of-range,
  • ORP overfeed,
  • pH overfeed.

The display stops flashing when the condition is corrected. To reset the overfeed timers, turn the feed mode to off and then back to Manual or Auto.


The ideal values are set as default values.  They can be adjusted by the operator at any time.  To reset all factory default values, press ORP and pH for 5 seconds.



Adjustable from 400 to 900 mV


Adjustable from 4.0 to 10.0


Platinum electrode with 10-ft (3 m) cable


Glass electrode with 10-ft (3 m) cable


ORP (3 digits) and pH (2 digits) LEDs


Manual, automatic, proportional


Setpoint, calibration, limits, feed rate


LEDs for feed mode, feed status, alarms


Audio, visual and remote alarms
Out-of-range limits and overfeed safety timers


Polystyrene 9x7x4 in. (22x18x10 cm)


110V, 230V or 24 VAC (specify)


PVC tees for 1-1/2" or 2" line


5 years on electronic module
1 year on all other parts


12x12x12-in (30x30x30 cm) carton
8 lbs (3 kg) without pumps
16 lbs (6 kg) with 2 chemical feed pumps

Technical Bid Specifications

Part #





Chemtrol 250 Digital ORP and PH Controller



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Automated Chemical Controllers

Chemical Feed Pumps

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