Revising part one: Water quality and chemistry


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Revision questions and answers for week one's water quality and chemistry module.

Congratulations on reading through the diploma materials for week one. Now let’s revisit some of the key pointers for it.

In this quick revision, the important thing to remember is that you are aiming to pick out the specific facts relevant to the question. The final test at the end of the diploma will not be the kind of test that requires hundreds of words — no part of it runs as an essay. Instead, it will be conducted in the form of multiple-choice answers to a series of questions.

The layout below is a selection of practice questions, each of which probe your knowledge on the module you have just covered. Though they’re not laid out as multiple-choice questions and answers, they are designed to stimulate your mind to re-explore some of the main areas you’ll be tested on.

1) What are the five aspects of water? 

 

2) How much more acidic is water with a pH of 5.0 than water with a pH of 6.0?

 

3) What effect does biological filtration have on pH?

 

4) What effect does carbon dioxide have on pH?

 

5) What is KH a measure of in aquaria?

 

6) Is rainwater rich or deficient in calcium carbonate?

 

7) How many mg/l of calcium and magnesium ions make up 1dGH?

 

8) Which two forms can ammonia take in aquaria, and what are their chemical symbols?

 

9) What effect does salt (NaCl) have on nitrite toxicity in fish?

 

10) What effect does photosynthesis of plants have on oxygen levels in a tank?

 

11) What is the OATA recommended concentration for oxygen levels at 25°C in freshwater?

 

12) Why are tall, cylindrical tanks inefficient at gas exchange?

 

SCROLL DOWN FOR THE ANSWERS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Answers

1) Gas content, movement, temperature, chemistry, quality.

 

2) Water with a pH of 5.0 is ten times more acidic than water with a pH of 6.0.

 

3) Biological filtration lowers pH.

 

4) Carbon dioxide lowers pH.

 

5) KH is a measure of water hardness, specifically carbonate hardness.

 

6) Rainwater is deficient in calcium carbonate.

 

7) 17.86mg/l of calcium and magnesium ions make up 1dGH.

 

8) Free ammonia, NH3 and ammonium, NH4+

 

9) Salt lowers nitrite toxicity in fish.

 

10) Photosynthesis in tanks increases oxygen levels.

 

11) The OATA recommended concentration for oxygen levels at 25°C in freshwater is 6mg/l.

 

12) Tall, cylindrical tanks inefficient at gas exchange as they have a low surface area to volume ratio.