gunnstack

6mm thick glass is quite adequate for 4ft tanks. You will find that even 5ft tanks with the appropriate bracing are quite common. My 4ft tank is made from 6mm glass and has only a single brace on the top and is filled to within 40mm from the top and I have never had any problems even with the recent earthquakes here. I've had the tank for over 10 years and have only had to remove the old Silicon and renew it. If you are worried about the tank bowing (assuming it already has some bracing) you can always add more bracing. I have made smaller 3ft tanks from 5mm glass with one 75mm brace in the centre and never had a problem. Providing it is already braced or you put braces in place ( a single 150mm wide in the centre or two 75mm is quite adequate) you will have no problems. Regards Gordon

Some years ago I had a similar problem. I used the paper towl method but the problem kept recurring. I finally discovered that the silicone was breaking down. Run you finger along the join and if the silicone feels soft and mushy and comes away on your finger it's time to strip it out and re-silicone. This happened to two tanks which I had re-siliconed 6 months previously, when I checked the tube I had used I discovered it was over 2 years old and probably past it's use by date. A new tube solved the problem. Regards Gordon

I have had a long association with the paint industry and Silicone products were one of the mediums I worked with. "Some" silicone's require a certain amount of moisture to cure properly-the slower the cure the better the bond-but some moisture must be present. As the previous post mentioned spraying water hastens the cure (surface only!!) but does little to create a really permanent bond with the substrate. Silicone cures in a similar way to paint i.e. it forms a surface skin which allows the active ingredient to work slowly on the substrate and form a bond, gradually realeasing volatiles etc. via the " semi-open skin" . However if the product is allowed to skin too quickly then you can create a sitution where gas/moisture will be trapped within the skin causing air or moisture bubbles to form. Try rolling paint on a wall on a really warm day and you will see what I mean-you will have a mass of bubbles which require to be individually "pricked" - prick of a job and you will probably have to re-do it to make it look reasonable!! Regards Gordon

There are a couple of things you want to watch out for. Firstly make sure the Silicone you use is is suitable for fish tank use (check the fine print!). Secondly make sure it is still within it's use by date. I have used some aged Silicone and within 6 months it broke down. The Silicone you need is supplied by a number of companies and uses Acetic Acid as the curing agent. It smells like very strong vinegar. You can use it to seal tanks but only if the fish are already removed. The acetic acid will etch the glass giving you a really good bond If you use the product and are asthmatic or have other lung problems leave it to a professional. I have built and re-built tanks but you really do need to use an extractor system a mask or a fan to get rid of the fumes. Remeber you are working in an enclosed environment when working over a tank-the fumes wil rise upwards. Acetic acid is not of itself toxic but the lungs in particular are susceptible to the irritating fumes given off during the curing process. It is also a skin irritant so anyone with a skin problem should take appropriate precautions. If all else fails-read the instructions!! Hope this has been of some help. Regards Gordon

Ripcord is a water based chemical commonly used by commercial applicators to control many types of insects including flies, spiders etc. but available over the counter to the general public. We use it outside under the eaves, round the windows, any place where you are likely to get spiders or other crawling insects. We also use it on the calves when the Ausie biting fly appears!! You will find it at any Rural Supply (RD1, Farmlands etc.) outlets as well as hardware stores. It works well inside also but is very toxic to fish but can be used on indoor shrubs & plants. Also extremely good for controlling mites in the chook house and on the chooks. If you want to use it inside cover the tank with plastic sheeting for a few hours after application and leave the doors open. You would also be well advised to use a mask and goggles as the commercial applicators do because of the irritation it will cause to eyes and throat in a confined area. If your asthmatic you may have problems. Being water based it will be washed off on surfaces exposed to the rain. By the way if you are a smoker or have a discoloured ceiling from a gas or open fire the water and chemical wil tend to "pool" the discoloured areas causing little brown blobs-I know from experience so prefer to use Pyrethrum spray and fly sprays. Hope this of help. Regards Gordon

Pyrethrum sprays are not deadly to fish unless you have your tanks uncovered, even then the spray would need to be at massive concentrations to cause a problem. At very high levels of concentration the spray will cause an oily film to occur on the uncovered water surface-hence oxygen starvation and poisoning will occur. Being oily the Pyrethrum will not sink but will remain on the surface. I have used an automatic pyrethrum spray for 3 months now to control the fly problem-the only deaths I have had were two Green Barbs who fought themselves to a standstill!! So long as the tank is covered and the spray directed away from the tank(s) there wil be no problem. We live in a rural situation and get the odd flush of flies. They come in, take one whiff and are gone again. Those that choose to stay we either Zap with fly spray or we find dead in the morning anyway from the effects of the Pyrethrum. I have yet to see any fish die as a direct result of the sprays. But with all sprays you have to use common sense and caution- never spray directly towards the tank and if you have to use sprays as we do use then with caution. Regards Gordon

Personally I'm not in favour of bolting my tank to the wall. When Living in L.Hutt I observed a numer of times that when we had an earthquake that, while the wall could be seen swaying in one direction- the water in the tank was moving the opposite way. I think bolting to the wall would exacerbate the movement particularly if the swaying motion was parallel to the wall. Bolting your frame to the floor would be a better option (assuming you live on the ground floor) as the floor will tend to move less than the walls. Providing the tank is sitting on a reasonable thickness of polystyrene there's little chance of it shifting. If in doubt you could always stick the polystyrene to the base and stick the tank to the polystyrene, Ivé used strips of BluTack in the past. I remember seeing a tank once where the person had glued a 2nd central glass bracing strip (vertically) below the water line which had a number of holes drilled in it, a baffle really. This he reckoned greatly reduced the wave effect and pressure on the tank ends. You couldn't see the baffle as there was a strip of black plastic round the top of tank.

Hi Buzzy-for elbows have a look in Mitre 10, they have elbows for use with their irrigation systems 4 or 6 in a bag (black in colour). I used them to put my intake under the gravel and towards the front of the tank where most of the gunk gravitates to. They fit in the standard hoses supplied with most filters. To make a U bend you will have to use short pieces of hose. Just remember the more elbows you use the more you will restrict the water flow so you may have to open the valve fully to achieve a good level of flow. Hope this helps-regards Gordon.

Hi all-thanks for your info. By chance I was talking to a guy at Mitre 10 in Foxton about the problem who just happens to keep tropical fish (as well as build tanks etc.) He uses a pyrethrum spray to cope with the flies and has no problem with the fish (covered tank). Well by another coincidence a friend who has just moved to Levin has one of those expensive spray gizmo's that can be programmed a dozen different ways (about $170-unused) and has offered it to me for free!! There is a Santa Claus after all :lol: Regards Gordon.

Hi just a short question- I hope. At present we have a terrible fly problem at Foxton Beach. Open the door for 2 minutes and the ceiling is black with flys. A friend has offered us one of those Pyrethrum spray gismo's which you can programme. The question is will a constant spray of Pyrethrum afffect the fish-bearing in mind that all the tanks are covered. And will the pyrethrum if it does get into the tanks affect the fish-or plants. Regards Gordon.

Thanks Warren for your prompt reply. Now if ivé got the gist of this correct what you are saying is that I need to have some form of water "hardener" in the tank to keep the Ph stable such as limestone in some form or another? It's odd that you should say that as the gravel in the tank was originally "nicked" from Eastbourne beach (quite a few years ago- and I can't reveal where cos there's still plenty there for the picking) and had quite a bit of shell in it and I suppose by now the vast majority has dissolved. Presumably some small amount of any beach shell would do- or does Oyster shell have some particular significance-slow release eg,? Or is fertilising/Ph adjustment/hardness via whatever means a science or an art? Regards Gordon

Hi Warren-thanks for the info. You are correct about the soft water, we are on tank water. I do a 25% water change mostly every week and yes I do use Bicarb to raise the Ph in the way you describe. As regards macro nutrients what are we talking about here-the normal small weekly doses of plant fertiser such as Aqua Master plant food and Flourish Excel-or something else? Since removing a plant which I thought might be causing the problem, adjusting the Ph to neutral it's slowly creeping down again-so that eliminates the plant I think and back in it goes. When living in Lower Hutt I never had a problem growing plants and had no need to add fertilisers but since moving to a rural area and using soft water it's been an uphill battle trying to get the balance right and plants to grow. I would appreciate if you could enlighten me further as it appears you may also be using tank water. Regards Gordon

Hi-I have used Flourish Excel to get rid of BB algae without problem. I followed the recommendations re-double dosing to start with followed by weekly doses and use the appropriate amount after water changes. No deaths! I have a variety of tetras, Green barbs, Gourami's, Bristlenose, Threadfin, Dwarf Chain Loaches, one Chocolate Gourami (the other 2 died from unknown causes before trying the FE). I have had no further outbreaks of BB algae.

Hi again. Just to clarify a couple of points in my last post, the Sword plants seem healthy enough but I haven't seen much in the way of growth and they are supposed to be quite fast growing plants. One point I looked at is that the Ph drops to below 6.4 even though the water I use for changes is Ph neutral. I tested both the Flourish Excel and the Aqua Master and they are also Ph neutral. I then had a look at what plants I had in the tank and searched for info on them. One of the plants I have is the Japanese Rush and it says that this plant can "destabilise the water chemistry putting the inhabitants at risk" (and presumably the other plants as well?). Does anyone have this plant in their tank or know of problems associated with it? I will take these plants out anyway, bring the Ph up slowly and monitor for any downward movement and see what the result is. Regards Gordon.

Two questions: 1)I have two Amazon Sword plants in my tank which appear to be doing quite well but losing the bottom leaves which I belive is quite normal. I was told these plants feed primarily through their roots and require regular feeding. The question is which is the most suitable food? It was suggested to me some time ago that PlantTabbs would be OK on the other hand I was advised not to use them as they can contribute to algae growth so I'm a little confused. I have visited a number of sites but never found one that suggested any type of plant food for these plants. 2)I use Aqua Master plant food which is Phosphate free and the plants seem to thrive quite well on that, the algae level is low and all the plants require regular trimming. Are their better alternatives than Aqua Master or are they all pretty much the same? Regards Gordon