Are W/c's Really Needed!? (I Know, I Know, But Need Some Help

[PrincessKiara]

Hello all!
I know you've told me multiple times what I should do with my 238L tank and its 90-100L sump system, especially you, Teacher But my parents need to hear it. Can you believe the tank's previous owner told them to add bacterial supplement, change 30% of the water every month ("no more because I could kill the bacteria") AND fully stock the tank!? (Aren't the bacteria not free swimming!?) This is a guy who had no idea what I was talking about when I asked him not to scrub out the filter and to keep it moist so he wouldn't kill the nitrifying bacteria! And who also told me I could safely keep 7 discus and 2 angels in my size tank... (He let the filter medium, a 'sock filter', dry out anyway.)
I was told (

) that I must change 50L weekly, and that I can build a rainwater-filtration system to get the remaining 30L to complement the 20L of tap water I will be allowed to change. Could someone very experienced please explain the concept here?
Also, my pH is 6.0 (my biology teacher gave me a strip of pH-testing tape...), can/should I raise it to 7?
So anyway, I'd love it if someone could explain the following:
-Why bacterial supplements don't (usually) work
-Why it's necessary to change a set amount of water EVERY WEEK
-What happens if you don't do sufficient w/c's
-Where bacteria grow, and how they grow
-How I could build a simple filtration system to use the abundant rain that falls here
 
I did pay attention when I was told this, I would just like for someone more experienced than I to repeat it here so that my parents will finally see that while I don't enjoy doing w/c's, I must do them for the welfare of my babies.
Thanks a lot in advance!

 

[Blondielovesfish]

I'm by far no expert, but I'll try my best
 

Why bacterial supplements don't (usually) work

 
I believe it is because most of them do not contain the correct bacteria that we want to break down the ammonia and nitrite. I think it is also because you do not know how they were handled in transit - whether they were kept at a desired temperature, how long they were in transit etc.
 
 

Why it's necessary to change a set amount of water EVERY WEEK

 
Some people do their water changes fortnightly, but I think it is easier to do them weekly.
 
Water changes remove nitrate (and ammonia and nitrite if the tank is cycling), they also replace mernals that are used up by plants, fish and bacteria.
 

 
 
What happens if you don't do sufficient w/c's

 
 Old tank syndrome is the most common, where the fish are so used to living in filthy water that when you do a water change, the new water shocks the fish, often killing them.
 
Nitrate also builds up, which, if there is too much, turns to a type of acid that lowers the pH, and can cause massive fluctuations.
 

 
 
Where bacteria grow, and how they grow

 
They mostly grow in the filter, since it has the most oxygen and flow. But they are pretty much anywhere that has oxygen.
 
Not sure how they grow, though I imagine it is like other bacteria, where they split in half, creating two of them (I think this is what you're asking?)
 

 
 
How I could build a simple filtration system to use the abundant rain that falls here

 
No idea, sorry.
 
Hope that helps some If I made any mistakes, feel free to correct me.

 

[Maehlice]

 

-How I could build a simple filtration system to use the abundant rain that falls here

 
I've never done this, but I've read a lot about catching rainfall for drinking, gardening and "fishing".  I'll share the high and low points...
 
If you don't live in a big city where the air itself is questionable, rainwater requires zero filtration, because nature has already done all the work for you.  If you live near anything that makes the air questionable (big city traffic, refinery, power plant, etc), the rain may be picking up any variety of potentially unknown contaminants before reaching the ground.
 
Assuming your air isn't polluting the rain on its way down, your only concern is catching it cleanly and doing a basic mechanical filtration by way of a screen, filter foam and/or filter floss.
 
If you're concerned about waterborne pathogens, sunlight is the cheapest and easiest filter on the market.  Unfiltered sunlight (specifically the UV-A radiation) kills all kinds of nasties.  Put your rainwater in clear 2L bottles (plastic, never glass) and leave it out in the sun for a few hours to kill most of the bacteria.
 
Next in line would be boiling the rainwater to kill even more pathogens and sterilize it.
 
None of that removes chemicals, though (if you live near filthy air).  An active charcoal/carbon filter removes most heavy metals and chemicals.  Search YouTube for "DIY Canister Filter" to get some ideas for doing it on the cheap.
 
If that's too expensive or high-tech for you, the best filter in the world is nature -- specifically, plants.  Plants purify air AND water.  It's quite the miracle invention.  In your garage or basement or attic or backyard or wherever, set up an aquatic garden much like you would an aquarium but without the fish.  Any water you keep in the aqua garden will be purified by the plants and bacteria within it.
 
Fill your aquarium from the aqua-garden and the aqua-garden from the rain barrels.
 
NOTE:  With the right amount of plants and animals, it's possible to NEVER do water changes!  

  In my last aquarium, I cycled the water with a powerhead but otherwise ran no filter, never cleaned it, and only added water to make up for evaporation loss.  My levels were always 0-0-0 with minimal pH fluctuations.  I had the right amount of plants, snails, shrimp and fish to form a mini ecosystem of sorts.  I don't necessarily recommend doing it that way, since I'm not a marine biologist or water chemist, but I do like to throw it out there that waterchanges aren't necessarily as "biblical" or vital for controlling nitrates as we've all been trained to believe.

 

[daizeUK]

Can you believe the tank's previous owner told them to add bacterial supplement, change 30% of the water every month ("no more because I could kill the bacteria") AND fully stock the tank!? (Aren't the bacteria not free swimming!?) This is a guy who had no idea what I was talking about when I asked him not to scrub out the filter and to keep it moist so he wouldn't kill the nitrifying bacteria!
 
Also, my pH is 6.0 (my biology teacher gave me a strip of pH-testing tape...), can/should I raise it to 7?
 
-Why bacterial supplements don't (usually) work
-Why it's necessary to change a set amount of water EVERY WEEK
-What happens if you don't do sufficient w/c's
-Where bacteria grow, and how they grow
Thanks a lot in advance!

If you add a bacterial supplement then the bacteria will be initially free swimming.  It takes time for them to adhere to surfaces.  They will adhere to whichever surface gives them the best advantage in terms of nutrients and oxygen, this is normally inside your filter.  When you add a liquid bacterial supplement it is usually a good idea not to change the water for a couple of weeks and most bottles will carry instructions about this on their labels.
 
The effectiveness of the bacterial supplement depends on which one you buy - many are useless but some do have a proven track record.
 
Your tap pH is very low and you may find it harder to culture bacteria at pH 6 as they prefer much higher pH.  They will also need carbonates which could cause you problems if your water is very soft.  I don't have any experience with cycling at low pH (TwoTankAmin is the man to talk to, but he's currently out of action

) but you can add sodium bicarbonate (baking soda) to increase your pH/hardness during cycling and then gradually do water changes to lower it to your usual levels.  The bacteria will adapt if you do this gradually.
 
As Blondie said, the water changes are to remove nitrates from the water and replace minerals.  You can get away with fewer water changes simply by keeping your tank understocked.  Fewer fish means slower nitrate production.

 

[the_lock_man]

Dear parents of PrincessKiara
 
Blondie and Daize have pretty much got it spot on with their explanations, there isn't really anything that I could add to what they have said.
 
Instead, I would like to address what the "previous owner" said. As with so many facets of life, our current understanding of reality has changed over the years. 500 years ago, the greatest minds believed that Planet Earth was flat. We now know that this was not the case.
 
In fishkeeping, our current understanding has also moved on. Changing more than 30% of the tank's water in a month will NOT kill the filter bacteria, providing that the water going does not contain chlorine. Previously, water companies added chlorine to the water in order to kill bacteria which are harmful to humans, and this could potentially, at high concentrations, kill filter bacteria, especially immature colonies. Thus it was that common practice used to be to allow a bucket of water to sit for 24 hours, as this allowed the chlorine to "gas off" from the water.
 
Laterly, those same utility companies are adding chloramine, a compound containing both chlorine and ammonia, and this does not "gas off", so letting it sit for 24 hours is useless.
 
You are now able to buy a Water Conditioner product which will remove chlorine and chloramine (as well as a number of other potentially harmful substances) from your tapwater. These products work, more or less, instantly, and you can add treated water immediately.
 
This is why weekly 30%+ water changes are the most common practice amongst experienced aquarists.
 
I hope this helps your understanding of the advice we have previously given your daughter. If you have any further queries, please feel free to post them on the forum, and we will do our utmost to answer them to your satisfaction.
 
Best Wishes
The_Lock_Man
(but you can call me TLM)

 

[Chad]

You could do a 90% water change and not remove enough bacteria to cause a problem. The reason large water changes can be a problem is simply that it changes the water parameters drastically sometimes, like pH etc. The bacteria that operate filtration are on the surfaces of your filter and gravel and even the decorations. Though some bacteria live in the water the amount is not enough to alter waste processing (i.e. filtration).
 
What water changes do is remove excess nutrients from the water. These nutrients can promote algae growth in non-planted tanks and can harm fish, even causing death.
 
I recommend a smaller change each week. Say 10% -15% every week depending on the tank's stocking levels. There is no need to spend the money on the bacteria. A simple water treatment/dechlorinator is sufficient.

 

[Lunar Jetman]

If you don't live in a big city where the air itself is questionable, rainwater requires zero filtration, because nature has already done all the work for you.  If you live near anything that makes the air questionable (big city traffic, refinery, power plant, etc), the rain may be picking up any variety of potentially unknown contaminants before reaching the ground.

Assuming your air isn't polluting the rain on its way down, your only concern is catching it cleanly and doing a basic mechanical filtration by way of a screen, filter foam and/or filter floss.
 
If you're concerned about waterborne pathogens, sunlight is the cheapest and easiest filter on the market.  Unfiltered sunlight (specifically the UV-A radiation) kills all kinds of nasties.  Put your rainwater in clear 2L bottles (plastic, never glass) and leave it out in the sun for a few hours to kill most of the bacteria.
 
Next in line would be boiling the rainwater to kill even more pathogens and sterilize it.

Just one observation, how near is too near? Clouds can travel thousands of miles so isn't it possible that just because you live in the middle of nowhere that your rainwater comes from somewhere that does have a big refinery, power plant, etc?

 

[Maehlice]

...  If you live near anything that makes the air questionable ...

Just one observation, how near is too near? Clouds can travel thousands of miles so isn't it possible that just because you live in the middle of nowhere that your rainwater comes from somewhere that does have a big refinery, power plant, etc?

 
That's a good question -- one I can't say I ever considered.
 
I think most rain clouds form in the same region where their rain falls, but I know clouds can certainly travel hundreds of miles, so who knows.
 
I presume if the rain isn't literally passing or falling entirely through the polluted air, the pollution is likely insignificant.
 
I researched rain-catching primarily for gardening and lawn irrigation, so contaminants didn't concern me too much.
 
I trust the air where I live, but if I ever do capture rainwater for drinking or aquarium use, I'll probably have a few water samples tested in a lab for good measure.

 

[PrincessKiara]

Ah, sorry. I didn't clarify. I really don't know my tap's pH. My tank's pH is 6.0. Also, I already have fish, plants, and inverts, so would the baking soda still be safe to add?
We live in a pretty big city, hence my concern for filtration. eaglesaquarium suggested that I set up a filter on the roof so that our abundant rain can be filtered, as in nature, through a bucket filled with layers of carbon, sand and gravel, into a plastic Rubbermaid box, where I can readily take 30L a week out for w/c's.
I would however prefer the planted method, as it would also provide a place for me to propagate plants I later plan to add to my aquarium. Would it work with just a plastic box, substrate, plants and sunlight? Or would my Teacher's suggestion work better?
Thanks again guys! I will be showing this thread to Mom today!

 

[daizeUK]

Sorry, I made an assumption that you were doing a fishless cycle which I shouldn't have, I wouldn't try to use baking soda to regulate your tank pH if there are fish in it.  Any idea why your tank pH is so low?
I wouldn't use rainwater in the middle of a city.

 

[Maehlice]

Sorry, I made an assumption that you were doing a fishless cycle which I shouldn't have, I wouldn't try to use baking soda to regulate your tank pH if there are fish in it.  Any idea why your tank pH is so low?
I wouldn't use rainwater in the middle of a city.

 
I agree to not use Baking Soda -- at least not directly in the tank.  Anything that drastically or quickly changes pH can shock and kill just about anything in the tank.
 
You can add crushed coral or cuttlebone to the tank to slowly increase the pH (and hardness to an extent).  You can also begin adding slightly-more-basic water during water changes to slowly bring it up over a couple weeks/months.
 
I, too, would like to know why the pH is so low.  If the water going in is that low, then it makes perfect sense.   In that case, you'd just need to slowly adjust the water going in until it's the pH you want.  If, however, the water goes in higher than that and then drops in the tank, managing pH is going to be tough.
 

We live in a pretty big city, hence my concern for filtration. eaglesaquarium suggested that I set up a filter on the roof so that our abundant rain can be filtered, as in nature, through a bucket filled with layers of carbon, sand and gravel, into a plastic Rubbermaid box, where I can readily take 30L a week out for w/c's.
I would however prefer the planted method, as it would also provide a place for me to propagate plants I later plan to add to my aquarium. Would it work with just a plastic box, substrate, plants and sunlight? Or would my Teacher's suggestion work better?

Both.
 
If you choose to utilize rainwater in a city, you must have some method of removing chemicals.
 
In the rooftop filter, "layers of carbon" is the key in that it is a form of chemical filtration.  Sand and gravel are mechanical filtration to remove debris.  Carbon eventually loses its potency, though.  In aquarium filters, most people change it every 4 weeks.  Considering less water will be passing through your rooftop filter, it may last longer.  I don't use carbon, so I have no practical experience on which to make a guess at its longevity.
 
If you choose the planted aqua-garden method, consider that chemicals have to go somewhere.  Those chemicals go into the plants and the soil and whatnot.  Especially If your fish will be eating those plants, you may still introduce some amount of chemicals into the aquarium.  How much, I don't know.  It's probably an insignificant trace amount, but I also know I wouldn't eat anything out of the filter.
 
In addition to "plastic box, substrate, plants and sunlight", you'll want some form of circulation.  Just about any powerhead or fountain/pond pump should do fine.
 
Consider, also, that direct sunlight will, without fail, permit algae to grow.  Especially if the algae is waterborne (the water itself turns green), you risk introducing that same algae into your tank.  It's not a major concern, but one worth considering.  Just like you would with store-bought plants, be sure to scrub and treat them before introducing them into your aquarium.

 

[Blondielovesfish]

How exact is your pH tester?
 
If your pH was measured in whole numbers, then your pH could very well be higher than tested.

 

[PrincessKiara]

I don't know. My biology teacher just ripped a strip off a roll of pH testing tape. It's not even specifically for aquaria, just something he had lying around. The color the tape turned exactly matched the "6.0" reference square.
As for algae, I really don't mind it, and I would love to have a place to propagate plants for later use in my aquarium. I have livebearers, literally hundreds of snails and several cories (I know they don't do much, algae-wise, but still). Also, I have a magnetic scrubby for my tank, which I plan to overplant LOL.
As for circulation, Teacher suggested this pump, since I have no outlets on my roof, but I'd have to figure out a way to keep the thing dry.
If I use the plant method, how long would I have to leave the water in with the plants?
Which method is more effective/safer?
Thanks again, y'all!

 

[Maehlice]

If I use the plant method, how long would I have to leave the water in with the plants?
Which method is more effective/safer?

 
As much as I like the planted method, using active carbon is likely the most effective and safest, because there's little/no question about whether the water has been filtered.  If it passes through the carbon layer, it's clean ... simple as that.
 
The same thing applies with the planted method but at a much slower rate.  As the water passes through the plant's cellular structure and is processed through photosynthesis, it is slowly purified.
 
As you've noted, though, there's a question of how long that takes.  That will depend upon how many plants are in there and how CO2-rich the water is.  Water and CO2 are both required for photosynthesis.  More CO2 & light = more photosynthesis & water processing.
 
EDIT:  Fertilization is also needed/recommended.
 
In a high-tech CO2-dosed tank with excellent circulation, fertilization, and lighting, I bet the water could be fully cycled in a day.  In a passive system like this, I'd give it at least a week.
 
If your aqua-garden is twice the size of your water change (60L), and you're changing the water once a week, I think that's sufficient.  (If I was drinking it, I'd leave it in there a month for good measure.)
 
If your display tank is also planted, the purification process will continue further in the main tank.  If you use a carbon filter in your main tank, even better -- introduce the new water into that filter to help clean up anything the aqua-garden may not have circulated.
 
 
P.S. - I'm not a chemist, so if you have any serious concerns about the rainwater quality, have it tested.  Then after you've purified the water (with whatever method), test it again to verify it's doing what's expected.
 
P.P.S. - Sorry for the long posts.  I type too fast.

 

[Maehlice]

I've slept since my last post, and I'd like to add something important responding, again, to the question of which method is more effective/safer:
 
As mentioned before, carbon eventually loses its potency and must be changed.  Otherwise, its chemical filtration becomes non-existent.
 
If you're not going to be monitoring and changing the carbon, the planted method is superior.