The Swimming Pool "Resource on The Web"
Fequently Asked Questions
A selection of questions we have received, and their answers
We do get a huge number of questions emailed to us, and whenever possible - time permitting we do try to answer as many as we can. Obviously, we cannot normally discuss detailed operational procedures for specific equipment, and we do not attempt to give complex instructions for major works such as building pools, replacing vinyl liners, or servicing equipment. We will not discuss the merits (or otherwise) of Branded Products. We also try to avoid encouraging pool owners to carry out any specialized work which really should be undertaken by professional pool engineers.
The answers we offer are based on our experience, and current conditions, recommendations, regulations, and Codes of Practice in the UK. Some advice, while valid in the UK may not be acceptable or practical in some other countries.
DISCLAIMER:- All the information and advice on these web pages is given in good faith and believed correct and accurate, but we cannot be responsible for any form of loss, damage or injury, however caused, through the use of any information or advice detailed here. Please be sure to also read the disclaimer on the Welcome Page.
COPYRIGHT:- All the information on these pages are for your PERSONAL USE. You may freely download, and retain anything for your own use that appears on this site provided you also retain and include a reference to this site and this copyright notice.. However, any part or whole of any article, text, or information that originates from this site may not be included in any publication, commercial literature, etc., etc., on any other web site, - or in any area where commercial or personal gain is conceived, without the express permission in writing from Malcolm R Bartier.
TOPIC: Baquacil Conversion
QUESTION: I am currently treating a 35,000 gallon in ground pool with baquacil, I would like to convert to chlorine without having to drain the pool to do so. Do you have any procedures that would allow me to do this?
ANSWER: Unfortunately, Baquacil reacts with chlorine to produce large quantities of a sticky orange-ish residue. It is sometimes possible to conteract this reaction by using very large amounts of shock chlorine - but we never recommend that procedure. Realistically, your only option is to drain the pool, flush or replace the sand in the sand filter, and start afresh.
TOPIC: Adding Muriatic Acid
QUESTION: Can you tell me why muriatic acid is added to swimming pools, and about how much?
ANSWER: pH control is an essential part of pool management. Muriatic acid is added to lower the pH value to the correct level. How much acid is added depends on a number of variables.
TOPIC: Liner Replacement
QUESTION: I have a 18' round pool and the liner needs to be changed, the pool is about 5 years old. Can you direct me to or tell the correct or (easy) way to install anew liner with pro looking results?
ANSWER: Installation of the liner depends on the type of pool and the method of holding the liner in place. With an overlap liner, it is often necessary to dismantle the top rails/copings. The liner is then streched out over the pool like a drum skin and centralized. water is then slowly run onto the liner causing it to sag. As the weight of water increases the liner is slowly and evenly lowered to the floor, and then carefully allowed to spread out ... evenly lowering the liner all the time. Once there is about 1 - 2 inches of water all over the floor of the pool the liner can be adjusted so that there are no wrinkles in the sides. The pool can then be filled and the top rails re-assembled.
TOPIC: Calcium Hardness
QUESTION: Last year I discovered the hardness level was 500+ ppm so I drained about 1/3 of the pool volume and replaced it with tap water. The level dropped to 350ppm. This year the level is again 500+ppm. I checked the hardness of our tap water and it is barely detectable. I don't use calcium chloride for chlorination. What do you think the problem could be due to and how do I correct it?
ANSWER: It sounds as though one or more of the following applies
(a) You don't backwash frequently enough.
(b) You don't have a pool cover - or you leave the pool uncovered for long periods.
(c) You run the pool temperature too high.
QUESTION: According to the type of filter I have (Cellular), there is no way to backwash. If this is incorrect, please let me know.
The pool is uncovered because the climate is rather warm--North Texas.
I only heat the spa from time to time--never the pool. Pool temperatures my reach 88deg in summer, though.
ANSWER: >>>According to the type of filter I have (Cellular), there is no way to backwash. If this is incorrect, please let me know.<<< - I think that here is the root of your problems. Because you have to remove your filter cartridge and clean it manually, you don't ever drain off some of the water and replace it with fresh, as is done with sand filter backwashing.
>>>The pool is uncovered because the climate is rather warm--North Texas.<<< - Again, evaporation will cause a loss of water (as H2O only), so calcium, and all other residuals will steadily increase.
I would suggest that you drain off and replace a percentage of water each week. Get a Calcium Hardness test kit - do a weekly test, and this will help you determine how much water to replace each week. I would guess at around 4 - 5%.. You could also try to cut down on evaporation by covering the pool when not in use. A simple sheet of building polythene on the surface would be sufficient to stop evaporation taking place.
TOPIC: Filling in a Pool
QUESTION: I have just moved into my mother's old house which already has a pool albeit in a state of dis-repair. Sadly, due to the cost issues and plans for a future family I feel that I should fill in the pool and return the garden to grass (the pool and patio take up almost all the back garden). I know you may feel I am mad but I would appreciate any advice as to what materials can be put into the hole to avoid any subsidence problems in the future. Are their other factors that I should have thought about ie existing Pipework etc and do you think I am doing the right thing?!!
ANSWER: I always feel that it is a total waste to fill in a perfectly good pool. If you really HAVE to take it out of use, why not try to simply preserve it. It could be filled with sand and decking placed over it. You would need to sink a pipe with a submersible to keep any water drained out of the shell. When you are ready, you can remove the decking and sand, wash out the pool shell and clean it up ready for filling and use.
TOPIC: Pool Liner Stains
QUESTION: I have brownish black stains or algae on the bottom of my vinyl pool in ground. It almost looks like dirt. I have treated for brown algae and also for metal stains but it is still there. It is creeping and growing larger. Any suggestions?
ANSWER: This may be a common bacteria found in the ground - Asperilus Niger.The staining from this looks similar to "candle soot" The usual way to destroy this is to flush chlorine behind the liner. You may be able to do this by first lowering the pool water level and then pouring chlorinated water behind the liner, and hope it gets under the floor to kill this.
TOPIC: Cloudy Water
QUESTION: I opened my inground pool several days ago.24,000 gallons of water. I put 10 gallons of sodium hypochlorite (commercial grade used in public pools) into my pool. The water is cloudy, and getting worse. I had the same trouble last year with 3" tablets. The total chlorine ( tested at pool place) is 6.6. The free chlorine is 0. Combined Chlorine is 6.6 pH is 7.6 They want me to put 15 bags of BURN OUT into the pool to break loose the chlorine. Last year they told me the same thing, and it did not work on two trys. Something is blocking my chlorine. Do you have any suggestions as to what could be the matter? We used to use lithium Hypochlorite, and never had any problems. It is not available to us now.
ANSWER: Sounds as though you run your chlorine level too low. This causes chloramines to be formed. Chloramines "soak up" free chlorine. Some types of chloramines are very difficult or impossible to "burn out" with a shock dose. These can only be controlled by regular dilution with fresh water. Check your Cyanuric Acid level as well, to make sure this is not too high (over 50 ppm) as this could cause "Chlorine Lock".
QUESTION: I would like to know what to put my pool dial on to vacuum.. I don:t want all the water to go the ground. because I have to keep puting water back into the pool. I have a inground pool and I am new at this. when I vacuum I want it to go into my filter.not on the ground.
ANSWER: Unfortunately, it is fact of life that you have to regularly replace some of the water in a pool. Another thing to consider is contamination of the filter media. It is always a good thing to vacuum to waste rather than contaminating the filter. If you don't regularly replace some of the water in your pool, the residuals will quickly build up possibly causing a complete failure of the water disinfection and possible damage to pool equipment.
TOPIC: Changing Sand in the Filter
QUESTION: How do I change the sand in the filter system-I cannot get my pool water to clear this summer, my pool is 8 years old, a 16 x32 inground vinyl liner. I have been advised to change the sand,as I have never cleaned the sand before. Can you give me some direction?
ANSWER: Without knowing the make and model of your filter, it would be difficult to give consise instructions. There are a number of considerations to check during a sand change, and it may be best to call your local pool engineers and have them change the sand for you. It is not usually a very expensive process.
TOPIC: Green Pool Water
QUESTION: I have a problem with a green pool.I have added 2 x 20litres of hypochlorite and circulated for 5 days-gone cloudy but still green-ph 7.4 to 7.6-now have added floc-hope to see a clear pool in the morning! I have just inherited the pool and the level of cyanurate is very high-255ppm-is this the reason why the liquid chlorine is not bleaching the algae-?
ANSWER: Absolutely!!! ..... at this level the chlorine is almost certainly locked!! To reduce the cyanuric acid level to the maximum acceptable, you would need to replace about 80% of the pool water. Completely draining and starting again appears to be the best idea. Check with your pool builder if you can safely drain and refil your pool without structural problems.
TOPIC: Cloudy Water
QUESTION: Last year, we were constantly having to correct chemicals. We tried stabilizer, but that didn't seem to make much of a difference. We are ready to open our pool this year, and it is in a mess. Due to health problems our pool didn't get closed correctly last year and has sat all winter without a cover. It is a disaster!! So far, we have checked the filter, lines and electrical connections, Checked the Ph and raised it accordingly, (it is now reading 7.6) and we have add 6 lbs of shock. The green is gone, but now we are left with a aqua color, very dense. We have added clarifier, and it is clumping nicely. The chlorine level is very high. Now, after all that, here is our question: How do we get this under control and keep it there. It just about wore us out last year trying to keep it stable.
ANSWER: >>>Checked the Ph and raised it accordingly, (it is now reading 7.6)<<< ..... you really should have left it alone if it was low. Chlorine works far quicker at a pH value of 7.0, or 7.2 than at 7.6. I am wondering if you meant "lowered" the pH. Anyway. 7.6 is still a bit to high for your problems - get it down to around 7.2.
>>>> We have added clarifier, and it is clumping nicely.<<<< ....... a good sign - if it is collecting in the pool, remember to vacuum directly to waste - NOT through the filter and back into the pool
>>>>How do we get this under control and keep it there<<<< ......; a "little and often" is the secret. Also ..... if your required chlorine level is 1.5 ppm and your required pH value is 7.4 pH ... what action do you take if you check your pool and find the readings are exactly correct???? ................ think about it!!! ...........If you said "do nothing" then you are wrong!!!! - the chlorine level will only go Down!! ... and the pH value will usually only go Up!! .... so you must ADD the required chemicals so that the NEXT time you test the water - the levels are STILL correct. This is the elusive secret of Pool Care
TOPIC: Various Questions
QUESTION: There are one or two questions I have after reading your pages, however, and would welcome a reply if you are able to give one - They are:-
Copper sulphate is often used here as an algaecide. You do not even mention it - positively or negatively. Is there some problem with using it?
- You suggest that the only solution to a build-up of cyanuric acid is dilution of the water via backwashes. Does soda ash not neutralise the cyanuric acid?
(Water out of the tap here is not treated. When a great deal of water is added to a pool, therefore, the pool usually goes green. This prompts putting in more chemicals, cleaning and backwashes which, of course, means adding yet more water . . and the cycles starts all over again! The only answer I have found is to add water very slowly so that the chemicals in the pool have time to work on it as it comes in)
- Why should DiChlor powder and Trichlor tablets not be used for shock treatment? Is it because of the build-up of cyanuric acid?
ANSWER: >>>>>- Copper sulphate is often used here as an algaecide. You do not even mention it - positively or negatively. Is there some problem with using it?<<<< - No problem at all .... there is always something omitted from information such as that on our site. Maximum Cu levels should not exceed 1 ppm. Just remember that Cyanuric Acid attacks copper - so high levels of Cyanuric Acid in the water can destroy or reduce the algaecidal effect of the copper.
>>>>> You suggest that the only solution to a build-up of cyanuric acid is dilution of the water via backwashes. Does soda ash not neutralise the cyanuric acid?<<<<< - No! .... Cyanuric Acid is a weak organic acid and has negligable affect on pH values - so pH correction is not an issue with this residual. It is the Cyanurates which have to be controlled.
>>>> (Water out of the tap here is not treated. When a great deal of water is added to a pool, therefore, the pool usually goes green. This prompts putting in more chemicals, cleaning and backwashes which, of course, means adding yet more water . . and the cycles starts all over again! The only answer I have found is to add water very slowly so that the chemicals in the pool have time to work on it as it comes in)<<<<< - You could try adding chemicals as the water level increases - so maintaining the chemical levels continuously
>>>>> Why should DiChlor powder and Trichlor tablets not be used for shock treatment? Is it because of the build-up of cyanuric acid?<<<< - Trichlor tablets release chlorine slowly so they cannot "Shock" (think of heating a pan with a candle) Dichlor chlorine does contain a high percentage of cyanuric acid - and shock dosing will increase this to an unacceptable level. Dichlor - being a chloro-isocyanurate, is not as aggresive at shocking as non-stabilized chlorine.
TOPIC: I want to build my own pool
QUESTION: I don't have a pool yet, but would like one. Can you suggest a good practical book I can get so I can understand about pool and spa types, design, maintenance, liner or concrete and so on. I would like to do as much deign and building work as is practical myself. The pool would be about 8x4m indoor.
ANSWER: I would be
VERY wary of a pool designed by someone not familiar with
swimming pool / spa design. Frequently, we have to visit a
"problem" pool - only to find it was designed and built
by someone with no previous experience. Some of the requirements
are very subtle - some are quite profound.
We have seen a number of pool "Installers" . . simply 'appear' . . because someone bought a a ready made Pool Kit,. . . found the installation easy . . and immediately considered themselves a "Pool Installer" and set up a business. Quite often, these people do more harm to the pool industry than anything else ever can. I could write a book, simply based on the abysmal workmanship, design and installation by some so-called "Pool Installers".
Please understand . . designing and building a pool . . especially an indoor pool . . requires a considerable amount of specialist knowledge. You will be spending a significant amount of money, which, if things go wrong, could be COMPLETELY wasted!!!! The knowledge needed cannot simply be looked up in a book.
Please . . if you want to be 'involved' in the the design and building of your pool, use the services of an experienced engineer/installer to oversee your ideas. A number of installers will happily work with the owner - checking his work at each stage before they allow him to progress to the next stage. The installer/engineer will be able to suggest the most appropriate equipment etc.etc. and make sure that the work is up to the required standard.
Even with the basic installation of the plantroom equipment, some maintenance experience is needed if the plantroom layout is to be "engineer friendly"
I hope this helps you understand the situation, and hopefully enables you to have you pool sucessfully built, and give you years of trouble free enjoyment.
END OF THE QUESTIONS PAGE