Safety & Problem solving

On the labels it clearly says how to use Melpool products and what you should pay attention to. Nevertheless, we would like to point out the following:

  • Always add chemicals to the water, never the other way around
  • Read the instructions on the label
  • Store chemicals in a dry and cool place. Do not store near flammable material.
  • Never mix chemicals
  • Never use empty packages of disinfection products to store other chemicals
  • Only use melpool 70/G or 70/20 in suitable dosage equipment
  • Keep chemicals and test sets out of reach of children
  • In case of fire with chemicals only extinguish with water, do not use a powder fire-extinguisher
  • Close packaging of containers after usage if spilled on clothing, take them off immediately. Then wash clothing straight away.


Eye/skin irritation or 'chlorine scents'

- PH value
- Presence of chloramines due to organic pollution combined with free chlorine

- Test the water and correct the pH value if necessary
- Super chlorinating eliminates the combined chlorine and turns it into free chlorine. The smell and irritation will disappear.

Free chlorine disappears fast

- High bathload
- Stormy weather, rain or high temperature
- Stabiliser level is too low

- Super chlorinating
- Check the stabiliser (cyanuric acid) level and use Melpool ICA. Switch to a stabilised chlorine product

PH value difficult to adjust

- Total alkalinity (TA) too high

- Check the TA and correct with Melpool PH- if necessary

Non-stable pH value (pH value fluctuates)

- Low total alkalinity (TA)

- Check the TA and correct with melpool TA+ if necessary


- High pH value and / or total alkalinity (TA)
- High calcium hardness (CH)

- Check the pH value and the TA and correct with Melpool PH- if necessary
- Add soft water. Do not use a chlorine product, which contains calcium, like Melpool 70/G and 70/20

Corrosion of metal parts

- Low pH value

- Check the TA and the pH value and correct with Melpool PH+ and if necessary, with Melpool TA+

Cloudy or milky water

- Bad circulation / filtration
- Large quantities dissolved solid substances or calcium hardness (CH)
- High pH value and total alkalinity (TA)
- Too much organic waste

- Check the pump and filter. Backwash and clean filter. Use Melpool PAC to speed up the process.
- Let the water out of the pool for 1/3 until ½ and fill up, use fresh water soft water.
- Do not use a chlorine product, which contains calcium, like Melpool 70/G and 70/20.
- Check the pH value and the TA and eventually correct with Melpool PH-, which lowers the pH value as well as the TA.
- Apply super chlorinating to oxidise organic waste.
- If necessary, use Melpool PAC to flocculate the remaining floating parts.

Cloudy green water

- Presence of algae

- Apply super chlorinating
- If necessary, repeat super chlorinating every 24 hours until the green colour is gone.
- Floc out the dead algae with Melpool PAC and remove them with a pool vacuum cleaner afterwards.
- From now on use Melpool QAC to prevent algae.

Clear but coloured water (black, brown, green/blue or reddish)

- Oxidised metal pollution of copper, iron or manganese

- Apply super chlorinating
- Treat the water with Melpool CAP flocculation.
- Add Melpool CAL
- Correct pH value, if necessary.

Stains (black, brown, blue)

- Metal pollution of copper, iron or manganese which are deposited in the water

- You may try and remove these stains with Melpool CAL. These stains usually are very difficult to remove. To prevent them is better than cure them. When evil is done, you should pump the pool partly or completely empty and treat the stains with acid. Ask your supplier for advice.

Fluffy black stains

- Presence of black algae on sides and bottom

- Black algae are very resistant
- Try and brush off stains
- Apply super chlorinating after at least 24 hours
- Repeat the super chlorinating every 24 hours until the stains have disappeared. During this treatment it is important to brush the affected spots regularly
- If after a treatment of 3 to 4 days the black algae are still visible, you should lower the waterline or pump the water away and directly put a 15% solution on the spots with a nylon or stainless brush. Remember chlorine can sometimes bleach the covering of the pool.
- From now on use melpool QAC as a preventive agent.


- Concentration algaecide too high

- Stop using Melpool QAC for several weeks.
- Decrease doses of algae killing products.


  • Do not touch DPD tablets with your hands, this may influence the test results.
  • Do not use a test kit with ortholodine (they do not have a long shelf life). Furthermore ortholodine measures total chlorine value and not the important free chlorine value.
  • Before every usage clean test kit thoroughly. Otherwise the test results may be influenced.
  • The chlorine value can be (because of wrong dosing) so high that you do not measure anything. The concentration exceeds the upper limit of the test scale of the testkit. It seems as if there is no chlorine in the water. To test the concentration in that case you can dilute the water 1 : 1 using tapwater. The test result should then be multiplied with 2.
  • Always take a sample from the water in the deepest part of your pool. Take a sample of water, which is about 30 cm. below the water surface.
  • Store test kits and tablets at room temperatures (out of reach of children).
    If the tablets show black spots they can no longer be used, because they are too old.