Balls to cover

[James WF10]

Just accidentally deleted what i wrote so will try again:
I've seen that a few people use plastic balls to cover their ponds, with company boasts of up to 75% reduction in heat loss.
I contacted a company who quoted just under £100 for a box of 1000. I figured i'd need roughly 3 boxes worth, so before delivery i'd be looking at approx £300.
A quick look on ebay shows 100's of sellers selling packs for kids ball pools at a relatively low price.
I reckon i could cover my pond with an assortment of coloured ball pool balls for a lot less than buying new.
My question is, would they be ok to use on a pond? i dont want to risk polluting the water.
Does anyone else use balls? do you recommend them?
Cheers
James

[Manky Sanke]

James,

For a small fee I can give you the "undeletable post" service.

Anyway, I assume that if these balls are small then the manufacturers will have considered the possibility that small children will suck them so they will have been made from a food grade plastic which means that there is no danger that they will leach toxic chemicals into the water.

Floating balls on the surface of a pond will obviously prevent heat loss but will also prevent normal gas exchange at the surface. Air pumps can be used to keep the water aerated but there is always the risk that the pump will fail or stop for some reason such as a power failure. With the surface covered by balls, aeration will fall to zero so the fish will be in danger of quickly suffocating and the balls will make it less likely for the failure to be noticed.

Polycarbonate sheets are an effective way to prevent heat loss. They would still hide the signs that an air pump had failed but, at least, there will be an air gap underneath to prove some measure of gas exchange.

[James WF10]

Cheers for the reply mate. Think i will stick with my plastic sheeting for this year but may look into plastic balls for next year. To be honest, i never run air pumps under the covers but my bottom drain feeds to a seive so i imagine this will add the air the pond needs? never had an issue with it before now, i heat it to about 6 degrees.
Is there an ideal heat to keep it at? i want it to stay relatively cold but just take the edge off with the heat to keep the cost of the heating down.
Cheers
James

[Manky Sanke]

James,

Following a few bad winters where uncovered pond temperatures were reported as falling close to zero and there were continuous reports of koi deaths I have been advocating that we don't expose koi to temperatures lower than 4°C.

My logic is that carp and the magoi from which koi have been bred have evolved to be quite used to winter lake temperatures of 4°C at the bottom where they would congregate during cold spells.

This is due to the temperature inversion at 4°C and the stratification that occurs in natural lakes. Temperature inversion isn't perfect because water can be stirred by winds so temperatures at the bottoms of lakes can go below 4°C but rarely do they go much lower than that for extended periods. Also, even in mid winter, carp will occasionally leave the depths and swim into colder water but they would rarely be exposed to sustained temperatures lower than that. So I think it unwise to expose koi to sustained winter temperatures lower than their ancestor fish were used to as they evolved.

As far as I can tell, it was the researcher, Luther Chien, who first proposed an idea which has become known as Aeromonas Alley. He found that there were no leukocytes (white blood cells) in the koi blood stream below 12.8°C. Leukocytes form the main part of the specific immune system and their absence at lower temperatures means that koi only have their non specific immune system which is far less effective against pathogenic bacteria.

Some of the aeromonas species of bacteria are capable of using haemoglobin as a nutrient source and therefore represent a real threat to koi. If these bugs, or any similar species, are present in a pond whilst the koi have a weakened immune system they can become systemic (in the blood stream and affecting multiple organs). An infection of this kind is difficult to treat without antibiotics and is often fatal.

They aren't the only bacteria that could infect koi but he clearly picked on aeromonas because he felt that it was typical of the type of pathogenic bugs that could easily proliferate at temperatures below 12.8°C and arguably the one that can cause the most damage.

Bugs and other parasites also become far less active as temperatures fall, especially below 10°C (ish). As a rule of thumb, they can be considered active to some extent down to 4°C and to be pretty much dormant by the time the temperature is around 4°C or lower.

Many people will say that they maintain winter temperatures around 8°C and never have a problem. This doesn't prove that Aeromonas Alley doesn't exist because, if there aren't any pathogenic bacteria in the pond in the first place, they obviously can't ever cause trouble. However, if there are then maintaining a temperature where koi have an weakened immune system but pathogenic bacteria are still active, (albeit at a lower level), will put the koi at a disadvantage and open to infections which will become more serious as temperatures begin to rise again in spring.

Another view on heating was proposed by Jim Reilly who says that "koi are a four season fish" and need a winter period in order to "reset their biological clocks".

It was trying to reconcile the ideas of Luther and Jim that gave me the idea that a compromise would be to set a heater to maintain a 13°C minimum pond temperature though autumn. Then, as the coldest part of winter approaches, the stat setting could be reduced in stages so as to allow it to fall reasonably quickly to around 4°C to give the koi Jim's winter period. After that, as spring arrives, increase the temperature reasonably quickly to 13°C again until summer temperatures could maintain that temperature.

Both men are satisfied, the fish spend only a short time in Aeromonas Alley and the pond owner gets the advantage of the minimum energy bill possible, which I think is an ideal situation for all concerned.

For koi keepers who can afford to heat their ponds throughout the whole year and don't want the temperature to fall below 13°C there is another option that still allows the Jim Reilly "four season" winter period. Maintain the preferred summer temperature until winter sets in and then reduce the temperature at a reasonable rate to 13°C until spring, or at least for a few weeks, before raising it again to the preferred summer temperature.

That will give the koi a winter period without them being in the temperature zone where their specific immune system is effectively switched off.

[Geoff9]

Just to add I understand the wind can blow the balls out the pond so have to be kept covered with something, about 7 years ago a lot tried them as they were easier to bag up in the Summer but each one had to be cleaned of moss but found they had a limited use.

Regards Geoff

[kayoss]

I was one of those who tried the balls!

Pros:
Cheap (got mine in Early Learning Centre's end of summer sale for about £5 for 100)
Non toxic because kids are expected to put them in their mouths.
Good insulation (when pond is covered)
Easy to bag and store

Cons:
Continually retrieving balls from neighbour's garden so pond not always covered!
Aeration under the balls causes balls to ride up on each other creating an un-insulated area.
Nightmare to clean.
Can't see whether or not food has been eaten
If you haven't got a window, you CAN'T SEE THE FISH to check their welfare!!!

Only used them for one season and invested in some triple walled polycarb for the next winter - much better all round IMHO.
BTW, I never had a water quality problem while using them, so assume there was enough space between the balls to allow gas exchange at the surface,

Cheers

Bob

[James WF10]

Thank you to everyone for their feedback and input. I genuinly appreciate it and can see people have put a lot of time into their responses so again, thanks you all very much.
Definitely got some food for thought.
Thanks for the help.
James