Temperature matching during massive (80%) weekly water changes

THQ

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HI all, I'm setting up a 165G oscar/sth american cichlid tank with 27C/80F temperature.

Due to having several very big and messy fish, it was recommended that I do 80% PWCs weekly (I can only manage weekly on weekends).

My tap water is usually much colder. At moment it is 17C/62F, but can get much colder.

My LFS says they just match the temperature with the hot/cold water tap mixer on the faucet. However, I read somewhere that hot water tank water is not potable, so I would assume something is in there that may harm fish?

Alternative would be to slowly fill the tank with cold tap water with both 2 x 300W heaters in the tank fully submerged working hard to minimise the difference.

What are everyone's thoughts? Thanks.
 

TexasDomer

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I would just add the water back slowly so your heaters can catch up.
 

SnyperTodd

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I've always mixed water to the correct temperature. I've never heard of a situation where the cold water was potable but hot water wasn't. The water heater doesn't do anything to the water besides heat it up...

 
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THQ

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Just found this... now I don't know what to think.



However, Prime is meant to detoxify heavy metals, so maybe still ok. Still wouldn't drink from the hot water tap though... I think my mum was right.
 

AlyeskaGirl

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You are going to drive yourself crazy. Lol

Yes, Prime removes heavy metals. You can even dose 5x the recommended dose.

If you decided to add cold water into the tank very slowly after draining out 80%, that would take forever to fill up.
 

Rivieraneo

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i've always mixed hot/cold water with my faucet mixing valve when refiling my tanks and have had zero effects. Think about all those nasty old pipes your water has to travel through just to get to your house I wouldnt worry.
 

TexasDomer

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My cold water comes out at room temp (~76 F), so I would feel comfortable just adding it as is without mixing with hot, maybe taking an hour to fill the tank instead of the normal 1/2 hour it takes me.

I've heard in some cases hot water isn't potable too (growing up I was told never to cook with hot water from the tap - always start with cold water and heat if needed!), but sounds like Prime will take care of any issues for you!
 
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THQ

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Cool. thanks for reassurance guys! saved me a lot of hassle.
 

Aquarist

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Hello,

Another option is to use another aquarium or drum (for potable water) to filter, heat and pretreat your water for water changes. I do this myself as my pH is so high it is off the charts. After prefiltering, heating and treating my water for 7 days, all is well and I'm ready for my water change.

I use these 55 gallon drums:


IMO...adding cold water to your aquarium may throw your fish into temperature shock. Not a good idea.

Ken
 

Tolak

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The potability of your tap water depends on your water heating system. I've you've got a free standing gas or electric water heater you're OK, providing info on your water heating system if it's something other than this will help.
 

chromedome52

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I believe this is a case of what used to be true is not necessarily true any longer because of advances in materials and methods.

Water heaters used to be made with metal tanks, and heating the water in these tanks leached metal ions into the water. Some Electric heaters also had a metallic rod down the center to extend the life of the tank. Because of these, hot water tended to be high in metallic ions, often borderline toxic if ingested.

More modern tanks are made of different materials or have non-toxic coatings, and may be less hazardous. So what was once true may no longer be applicable.
 
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THQ

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Thanks for everyone's advice. I actually got a plumber yesterday that specializes in my hot water system brand to service mine and we got talking about this very issue. Turns out he is a keen fishkeeper too (african cichlids).

The water system I have is stainless steel, so won't corrode or leach into the water. The temperature inside the system must be kept > 60C (>140F) to kill legionella. This was another theoretical fear of drinking from the hot water system, that if the water wasn't hot enough you could contract legionella. However, most water systems are designed to get hotter than this by default.

Older vitreous enamel water tanks required a sacrificial anode that got gunked up over time with mineral deposits, and needed to be changed every 5 years or so. Most modern ones are stainless steel ones so don't.

At the end of the day, he says he has mixed his hot and cold water into his african cichlid tank with no issues for many years, so that's good enough for me.

Aquarist said:
Hello,

I use these 55 gallon drums:


Ken
Thanks, I've decided to use the hot water from the faucet now, but previously I actually planned to get 240L/63G food-grade wheelie bins to do this.



The wheels help with moving it around if necessary, and I am comfortable that if the plastic is good enough to store food in, it should be good enough for my fish.

Was planning to just keep a powerhead in the bottom to pump the water from the bin into the tank.
 

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As involved as you are in the water changes for your fish you may want to consider a setup like what I use.

1. Source water to a sediment filter.

2. Filter to a new generation water softener set to 3 ppm TDS.

3. Softener to a seconded sediment filter.

4. Sediment filter to a 5 stage R/O DI unit. Water is now at a ph of 7 with TDS of 1ppm.

5. From the R/O DI to 3 30 gal storage tanks (Brute trash cans) with a heater in the last one set to 78 degrees F.

I then adjust the water chemistry to the needs of the tanks it is going into.

I have the water at 78 degrees because that is what most of our tanks are set at. The neon tank is lower but the introduction of warmer water in small amounts is better than water that is colder to the other tanks.

Edit: I have been sitting here wondering about the necessity of 80% water changes weekly. The fish you list if memory serves are not as sensitive as Discus and the water change schedule you prepose is one I would use for them. What filtration are you going to use? At 160 gallons (US) with those fish I would go no less than 2,000 GPH turn over with a weekly light cleaning of the filter medium.
 
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THQ

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Thanks for the reply. My water comes out the tap very close to neutral and very soft, usually 1-2 dKH/GH, so I guess I am lucky in that respect. That setup is too complicated and time consuming for me unfortunately.

In the 165G I am planning to keep 1 Oscar, 1 Severum, 1 HeckeliI and 1 Uaru at this point. It is not overstocked but from the advice I have been given over at the Oscar forums a minimum water change schedule is 80% weekly once they are fully grown just to keep nitrates under control. I can't keep plants as a nitrate sink as oscars are like Godzilla to plants.

Most of the Oscar guys do twice weekly large changes, some even do every 2 days regularly. Apparently oscars are incredibly polluting fishes even for their large 3lb weight. They chew then spit out a lot of half eaten food, and and poo all day long. Luckily their personality makes up for their messiness


 

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